2-(Arylmethylenehydrazono)-4,4-diphenyl-1H-imidazol-5(4H)-one 3 underwent regioselective cyclization upon treatment with bromine in acetic acid containing sodium acetate to give the respective 3-substituted-6,6-diphenyl-6,7-dihydro-imidazo[2,1-c][1,2,4]triazole-5-one 4 in overall good yields and not the isomeric structure 5. In addition, compound 4 was synthesized by alternative method via reaction of compound 1 with different acids in acetic acid. The synthesized hydrazone derivatives were screened for their angiotensin II receptor antagonists activity and the results showed promising activity. Also, imidazo[2,1-c][1,2,4]triazole-5-ones 4 were screened for the antibacterial activity and the result revealed that two derivatives have excellent activity.