Synthesis of 4-amino-5-(3-bromophenyl)-4H-1,2,4-triazole-3-thiol (1), 3-(3-bromophenyl) [1,2,4]-triazolo [3,4-b][1,3,4] thiadiazol-6-amine (2), N-substituted benzylidene -3-(3-bromophenyl)-[1,2,4] triazolo-[3,4-b] [1,3,4]-thiadiazole-6-amine (3-7),1-(3-(3-bromophenyl )-[1,2,4 ]triazolo-[3,4-b] [1,3,4]-thiadiazole-6-yl)-4-substitutedphenyl azetidin-2-one (8-12), 3-(3-(3-bromophenyl)-[1,2,4] triazolo-[3,4-b] [1,3,4]-thiadiazole-6-yl)-2-phenylthia zolidin-4-one (13-17), 1-(3-(3-bromophenyl)-[1,2,4]triazolo-[3,4-b], [1,3,4]-thiadiazole-6-yl)-4-substi- tutedphenyl-3-((o-tolyamino)methyl) azetidin-2-one (18-27). Among all the synthesized compounds, Mannich products were found to possess wide spectrum of antibactderial and antifungal activities with lesser potency and among the mannich products, 22 and 26 were found most potent compound of the series.