Acyclic analogues of thiacloprid and related cyanoguanidine derivatives were prepared. Their Insecticidal activity against the American cockroach was determined by the injection method with or without metabolic inhibitor(s). Thiacloprid along with two cyanoguanidine analogues showed the highest insecticidal potency without the inhibitors, which was one twentieth that of imidacloprid. Metabolic inhibitors increased the activity by a factor of up to 100 for sulfur-containing compounds including thiacloprid, while the effect for the cyanoguanidine derivatives was much smaller. Most of the test compounds elicited impulses in cockroach central nerves with an initial excitation and subsequent block. Thiacloprid and its acyclic analogue were on a par with imidacloprid for blocking potency. As the blocking activity increases, the insecticidal activity measured with the metabolic inhibitors tends to strengthen.