In the present work 2-((1H-benzo[d]imidazol-2-yl)thio)-N-(4-(4-(1H-indol-3-yl)-8-methyl-1H-benzo[b][1,4]diazepin-2-yl)phenyl)acetamide 3ad, N-(4-(4-(1H-indol-3-yl)-8-methyl-1H-benzo[b][1,4]diazepin-2-yl)phenyl)-2-((5-methoxy-1H-benzo[d]imidazol-2-yl)thio)acetamide 4a-d and N-(4-(4-(1H-indol-3-yl)-8-methyl-1H-benzo[b][1,4]diazepin-2-yl)phenyl)-2-(benzo[d]thiazol-2-ylthio) acetamide 5a-d were synthesized in good yield in in-situ by cyclization of chalcones with substituted ortho-phenylenediamine. The chalcones were in turn prepared by Claisen–Schmidt condensation 2-(1H-benzo[d]imidazol-2-ylthio)-N-(4-acetylphenyl) acetamide and various 2, 5-disubstituted indole-3-carboxaldehydes in the presence of piperidine. The structures of all the newly synthesized compounds were characterized by their IR, 1HNMR, mass spectral studies and elemental analysis. All these compounds were screened for their in-vitro antimicrobial activity by agar plate diffusion method, Antioxidant activities: like, 1,1-Diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity (RSA), Ferric ions (Fe3+) reducing antioxidant power (FRAP), Ferrous (Fe2+) metal ion chelating activity. Some of the compounds have shown potent anti-microbial activity against all the screened bacteria and fungi and some have exhibited very good antioxidant activity.