A simple and efficient method has been developed for the synthesis of various 4-oxo-2-substituted phenyl-1,3- thiazolidine derivatives of 5-nitroindazole using conventional method. The series of 4-oxo-2-substituted phenyl-1,3- thiazolidine derivatives synthesized were structurally confirmed by analytical and spectral data and evaluated for their antimicrobial activities. Some compounds show that promising antibacterial and antifungal activities.