diff --git a/rmgpy/reaction.py b/rmgpy/reaction.py
index b4a808790e..b5cc88395f 100644
--- a/rmgpy/reaction.py
+++ b/rmgpy/reaction.py
@@ -1529,16 +1529,22 @@ def same(object1, object2, _check_identical=check_identical, _only_check_label=o
         else:
             return object1.is_isomorphic(object2, generate_initial_map=_generate_initial_map,
                                          strict=_strict, save_order=_save_order)
-
-    if len(list1) == len(list2) == 1:
+    maximum_length = 10
+    len_list1 = len(list1)
+    if len_list1 != len(list2):
+        return False
+    if len_list1 == 0:
+        # List is empty
+        raise NotImplementedError("Can't check isomorphism of lists with {0} species/molecules".format(len_list1))
+    elif len_list1 == 1:
         if same(list1[0], list2[0]):
             return True
-    elif len(list1) == len(list2) == 2:
+    elif len_list1 == 2:
         if same(list1[0], list2[0]) and same(list1[1], list2[1]):
             return True
         elif same(list1[0], list2[1]) and same(list1[1], list2[0]):
             return True
-    elif len(list1) == len(list2) == 3:
+    elif len_list1 == 3:
         if same(list1[0], list2[0]):
             if same(list1[1], list2[1]):
                 if same(list1[2], list2[2]):
@@ -1560,7 +1566,26 @@ def same(object1, object2, _check_identical=check_identical, _only_check_label=o
             elif same(list1[1], list2[1]):
                 if same(list1[2], list2[0]):
                     return True
-    elif len(list1) == len(list2):
-        raise NotImplementedError("Can't check isomorphism of lists with {0} species/molecules".format(len(list1)))
-    # nothing found
+    elif len_list1 <= maximum_length:
+        # Copy list to prevent changes to original input
+        l1=list1[:]
+        l2=list2[:]
+        x=0
+        while x<len(l1):
+            found_y = False
+            for y in range(len(l2)):
+                if same(l1[x],l2[y]):
+                    found_y = True
+                    del l1[x]
+                    x-=1
+                    del l2[y]
+                    break
+            if not(found_y):
+                return False
+            x+=1
+        return (len(l1)==0) and (len(l2)==0)
+    else:
+        # List is too long
+        raise NotImplementedError("Can't check isomorphism of lists with {0} species/molecules".format(len_list1))
+    
     return False