diff --git a/SynTemp/SynComp/__init__.py b/SynTemp/SynComp/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/SynTemp/SynComp/rule_compose.py b/SynTemp/SynComp/rule_compose.py
new file mode 100644
index 0000000..9315252
--- /dev/null
+++ b/SynTemp/SynComp/rule_compose.py
@@ -0,0 +1,163 @@
+import os
+import glob
+import logging
+from typing import List
+from SynTemp.SynComp.valence_constrain import ValenceConstrain
+from SynTemp.SynUtils.graph_utils import load_gml_as_text
+from mod import RCMatch, ruleGMLString
+
+logging.basicConfig(
+    level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s"
+)
+
+
+class RuleCompose:
+    def __init__(self) -> None:
+        pass
+
+    def _compose(rule_1, rule_2):
+        """
+        Compose two rules and filter the results based on chemical valence constraints.
+
+        Parameters:
+        - rule_1: First rule object to compose.
+        - rule_2: Second rule object to compose.
+
+        Returns:
+        - list: List of 'good' modifications where the resulting rules pass the
+        valence checks.
+        """
+        try:
+            # Attempt to match and compose the rules
+            m = RCMatch(rule_1, rule_2)
+            modRes = m.composeAll()
+            valence_check = ValenceConstrain()
+            goodMod, _ = valence_check.split(modRes)
+            return goodMod
+        except Exception as e:
+            print(e)
+            return []  # Return an empty list in case of failure
+
+    @staticmethod
+    def _process_compose(rule_1_id, rule_2_id, rule_path, rule_path_compose):
+        """
+        Process and compose two rules based on their GML files.
+
+        Parameters:
+        - rule_1_id (str): Identifier for the first rule.
+        - rule_2_id (str): Identifier for the second rule.
+        - rule_path (str): Directory path where the original GML files are stored.
+        - rule_path_compose (str): Directory path where the composed GML files
+        will be saved.
+
+        Returns:
+        - list: Composed rules from the two provided rules.
+        """
+        rule_1 = load_gml_as_text(f"{rule_path}/{rule_1_id}.gml")
+        rule_1 = ruleGMLString(rule_1)
+        rule_2 = ruleGMLString(load_gml_as_text(f"{rule_path}/{rule_2_id}.gml"))
+        rules_compose = RuleCompose._compose(rule_1, rule_2)
+        if rule_path_compose:
+            for key, value in enumerate(rules_compose):
+                filepath = f"{rule_path_compose}/p_{rule_1_id}_{rule_2_id}_r{key}.gml"
+                RuleCompose.save_gml_from_text(
+                    value.getGMLString(), filepath, key, [rule_1_id, rule_2_id]
+                )
+        return rules_compose
+
+    @staticmethod
+    def _auto_compose(rule_path, rule_path_compose):
+        """
+        Automatically find all GML files in the given directory and compose them pairwise.
+
+        Parameters:
+        - rule_path (str): Directory path where the GML files are stored.
+        - rule_path_compose (str): Directory path where the composed GML files will
+        be saved.
+
+        Returns:
+        - None: Composed rules are saved directly to the filesystem.
+        """
+        # Get all gml file names in the directory
+        gml_files = [os.path.basename(f) for f in glob.glob(f"{rule_path}/*.gml")]
+        gml_ids = [
+            os.path.splitext(f)[0] for f in gml_files
+        ]  # Strip the .gml extension to get IDs
+
+        # Compose each pair of rules once (i.e., (rule1, rule2) but not (rule2, rule1))
+        # Calculate the total number of compositions for progress logging
+        num_files = len(gml_ids)
+        total_compositions = num_files * (num_files - 1) // 2
+        current_composition = 0
+        for i in range(len(gml_ids)):
+            for j in range(i + 1, len(gml_ids)):
+                RuleCompose._process_compose(
+                    gml_ids[i], gml_ids[j], rule_path, rule_path_compose
+                )
+                current_composition += 1
+                if current_composition % 100 == 0:
+                    logging.info(
+                        f"Progress: {current_composition}/{total_compositions}"
+                        + "compositions completed."
+                    )
+
+    @staticmethod
+    def save_gml_from_text(
+        gml_content: str, gml_file_path: str, rule_id: str, parent_ids: List[str]
+    ) -> bool:
+        """
+        Save a text string to a GML file by modifying the 'ruleID' line to include parent
+        rule names. This function parses the given GML content, identifies any lines
+        starting with 'ruleID', and replaces these lines with a new ruleID that
+        incorporates identifiers from parent rules.
+
+        Parameters:
+        - gml_content (str): The content to be saved to the GML file. This should be the
+        entire textual content of a GML file.
+        - gml_file_path (str): The file path where the GML file should be saved. If the
+        path does not exist or is inaccessible, the function will return False and print
+        an error message.
+        - rule_id (str): The original rule ID from the content. This is the identifier
+        that will be modified to include parent IDs in the new ruleID.
+        - parent_ids (List[str]): List of parent rule IDs to prepend to the original rule
+        ID. These are combined into a new identifier to reflect the hierarchical
+        relationship in rule IDs.
+
+        Returns:
+        - bool: True if the file was successfully saved, False otherwise. The function
+        attempts to write the modified GML content to the specified file path.
+        """
+        try:
+            parent_ids = [str(i) for i in parent_ids]
+            rule_id = str(rule_id)
+            # Create the new ruleID by concatenating parent IDs with the original rule ID
+            new_rule_id = (
+                "p_" + "_".join(parent_ids) + "_r_" + rule_id
+                if parent_ids
+                else "r_" + rule_id
+            )
+
+            # Initialize a list to hold the modified lines
+            modified_lines = []
+
+            # Iterate through each line and replace the 'ruleID' line as needed
+            for line in gml_content.splitlines():
+                if line.strip().startswith("ruleID"):
+                    # Replace the whole line with the new ruleID
+                    modified_lines.append(f'\truleID "{new_rule_id}"')
+                else:
+                    modified_lines.append(line)
+
+            # Join all lines back into a single string
+            modified_content = "\n".join(modified_lines)
+
+            # Write the modified content to the file
+            with open(gml_file_path, "w") as file:
+                file.write(modified_content)
+            return True
+        except FileNotFoundError:
+            print(f"Unable to access the file path: {gml_file_path}")
+            return False
+        except Exception as e:
+            print(f"An error occurred while writing to the file: {e}")
+            return False
diff --git a/SynTemp/SynComp/valence_constrain.py b/SynTemp/SynComp/valence_constrain.py
new file mode 100644
index 0000000..b8ba1fd
--- /dev/null
+++ b/SynTemp/SynComp/valence_constrain.py
@@ -0,0 +1,101 @@
+import importlib.resources
+from SynTemp.SynUtils.utils import load_database
+from mod import BondType
+import logging
+from typing import List, Tuple
+
+
+class ValenceConstrain:
+    def __init__(self):
+        """
+        Initialize the ValenceConstrain class by setting up bond type orders and loading
+        the maximum valence data.
+
+        Parameters:
+        - None
+
+        Returns:
+        - None
+        """
+        self.btToOrder = {
+            BondType.Single: 1,
+            BondType.Double: 2,
+            BondType.Triple: 3,
+            BondType.Aromatic: 0,
+        }
+        maxValence_path = importlib.resources.files("SynTemp.SynComp").joinpath(
+            "MaxValence.json.gz"
+        )
+        self.maxValence = load_database(maxValence_path)[0]
+
+    def valence(self, vertex) -> int:
+        """
+        Calculate the valence of a vertex based on its incident edges.
+
+        Parameters:
+        - vertex (Vertex): The vertex for which to calculate the valence.
+
+        Returns:
+        - int: The total valence of the vertex.
+        """
+        return sum(self.btToOrder[edge.bondType] for edge in vertex.incidentEdges)
+
+    def check_rule(self, rule, verbose: bool = False, log_error: bool = False) -> bool:
+        """
+        Check if the rule is chemically valid according to valence rules.
+
+        Parameters:
+        - rule (Rule): The rule to check for chemical validity.
+        - verbose (bool): If true, logs additional information about the rule
+        checking process.
+        - log_error (bool): If true, logs additional information about the valence
+        checking issue.
+
+        Returns:
+        - bool: True if the rule is chemically valid, False otherwise.
+        """
+        try:
+            for vertex_pair in rule.vertices:
+                left_valence = self.valence(vertex_pair.left)
+                right_valence = self.valence(vertex_pair.right)
+                left_label = vertex_pair.left.stringLabel
+                right_label = vertex_pair.right.stringLabel
+
+                if left_valence != right_valence:
+                    raise ValueError(
+                        f"Valence mismatch: left {left_valence} vs right {right_valence}"
+                    )
+
+                if left_valence > self.maxValence.get(
+                    left_label, 0
+                ) or right_valence > self.maxValence.get(right_label, 0):
+                    if verbose:
+                        logging.info(
+                            f"Bad Rule for vertex {left_label} --->"
+                            + "Exceeds max chemical valence"
+                        )
+                    return False
+            return True
+        except Exception as e:
+            if log_error:
+                logging.error(f"Error checking rule {rule}: {e}")
+            return False
+
+    def split(self, rules: List) -> Tuple[List, List]:
+        """
+        Split rules into 'good' and 'bad' based on their chemical validity.
+
+        Parameters:
+        - rules (List[Rule]): A list of rules to be checked and split.
+
+        Returns:
+        - Tuple[List[Rule], List[Rule]]: A tuple containing two lists, one for
+        'good' rules and another for 'bad' rules.
+        """
+        good, bad = [], []
+        for rule in rules:
+            if self.check_rule(rule):
+                good.append(rule)
+            else:
+                bad.append(rule)
+        return good, bad