diff --git a/arc/species/converter.py b/arc/species/converter.py
index bd43deead0..d223a3725b 100644
--- a/arc/species/converter.py
+++ b/arc/species/converter.py
@@ -1730,13 +1730,15 @@ def to_rdkit_mol(mol, remove_h=False, sanitize=True):
     Adopted from rmgpy/molecule/converter.py
 
     Args:
-        mol (Molecule): An RMG Molecule object for the conversion.
+        mol (Molecule, ARCSpecies): An ARCSpecies or RMG Molecule object for the conversion.
         remove_h (bool, optional): Whether to remove hydrogen atoms from the molecule, ``True`` to remove.
         sanitize (bool, optional): Whether to sanitize the RDKit molecule, ``True`` to sanitize.
 
     Returns:
         RDMol: An RDKit molecule object corresponding to the input RMG Molecule object.
     """
+    if type(mol) == ARCSpecies:
+        mol = mol.mol
     atom_id_map = dict()
 
     # only manipulate a copy of ``mol``
diff --git a/arc/species/converter_test.py b/arc/species/converter_test.py
index 8a5b0ca3e6..e977d1aa00 100644
--- a/arc/species/converter_test.py
+++ b/arc/species/converter_test.py
@@ -3643,6 +3643,11 @@ def test_to_rdkit_mol(self):
         rd_mol_block = Chem.MolToMolBlock(rd_mol).splitlines()
         self._check_atom_connectivity_in_rd_mol_block(spc1.mol, rd_mol_block)
 
+        rd_mol = converter.to_rdkit_mol(spc1)
+        self.assertIsInstance(rd_mol, rdchem.Mol)
+        rd_mol_block = Chem.MolToMolBlock(rd_mol).splitlines()
+        self._check_atom_connectivity_in_rd_mol_block(spc1.mol, rd_mol_block)
+
         xyz = {'symbols': ('O', 'C', 'C', 'C', 'C', 'H', 'H', 'H', 'H', 'H', 'H', 'H', 'H', 'H', 'H'),
                'isotopes': (16, 12, 12, 12, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
                'coords': ((-1.3435816539552077, -1.2858724378615196, 1.2807152578949395),