In the present study, a series of N-[5-(phenyl)-1,3,4-thiadiazole-2-yl] benzamide and N-[5-(phenyl)-1,3,4-thiadiazole-2-yl] acetamide were prepared by refluxing with benzoyl chloride and acetyl chloride with 5-phenyl-1,3,4-thiadiazole-2-amine. 5-phenyl-1,3,4-thiadiazole-2-amine were prepared by oxidative cyclization of thiosemicarbazone (through condensation of aromatic aldehyde and thiosemicarbazide). The structure of new compounds prepared during present investigation have been authentically established by their IR,1H-NMR and Mass spectral studies. The antibacterial and antifungal activities of thiadiazole derivatives also reported. Some of these derivatives exhibit significant antimicrobial activity. Key words:  Thiosemicarbazone, Thiadiazole, antibacterial, antifungal.