diff --git a/test/inputs/compound_isSmiles_Pos_None.py b/test/inputs/compound_isSmiles_Pos_None.py
new file mode 100644
index 000000000..d66ffa8bf
--- /dev/null
+++ b/test/inputs/compound_isSmiles_Pos_None.py
@@ -0,0 +1,11 @@
+import pytest
+from ersilia.utils.identifiers.compound import CompoundIdentifier
+
+# testing for _is_smiles positive test when Chem is None.
+def test_is_smiles_positive():
+    parser = CompoundIdentifier()
+    parser.Chem = None
+    # Using Dimethyl ether SMILES representation as a valid string
+    smiles_text = "COC"
+
+    assert parser._is_smiles(smiles_text) is True
\ No newline at end of file