Syntheses are reported for 6-(methylthio, ethylthio, propylthio, substituted benzylthio and chloro)-3-(methoxy, unsubstituted and benzamidomethyl)-2-arylimidazo[1,2-b]pyridazines contg. methoxy, methylenedioxy and Me groups attached to Ph substituents. In tests of the ability of these compds. to displace [3H]diazepam from rat brain membranes, 3-methoxy-6-(3',4'-methylenedioxybenzylthio)-2-(3'',4''-methylenedioxyphenyl)imidazo[1,2-b]pyridazine (IC50 1 nM) bound most strongly; methylenedioxy groups were beneficial to activity whereas polymethoxy or di-Me substituents were generally detrimental.