Compounds in which two methyl groups of acetamiprid are replaced with a set of substituents were prepared and the presence of the two rotamers was confirmed from NMR spectra. The insecticidal activities against American cockroaches and houseflies were measured by injection methods with or without metabolic inhibitors. The modified compounds were weaker than acetamiprid in their insecticidal activities against both species. A metabolic inhibitor, piperonyl butoxide, increased the insecticidal activities and in combination with NIA 16388 enlarged the rates of increase. The neuroblocking activity of the compounds was measured with excised central nerve cord of the cockroach. Here also the substitution with bulky groups at the terminal site or on the amino nitrogen atom lowered the neuroactivity, the lowering rate being greater in the former. The insecticidal potency for the cockroach with both metabolic inhibitors correlated well with the neuroblocking activity when the hydrophobicity factor of compounds was calculated separately.