4-thiazolidinones are among t h e most extensively investigated class of organic compounds. Thiazolidin-4-one has been considered as magic moiety, which is a core structure in various synthetic pharmaceuticals displaying a broad spectrum of biological activities.They are widely used as anti-inflammatory, anticonvulsant, analgesic, antimicrobial,anti-HIV,CNS depressant, carcinostatic, antihypertensive and cytotoxic. In view of the wide spectrum activities of condensed 4-thiazolidinones, it was thought worthwhile to undertake the synthesis of heterocyclic systems in which 4-thiazolidinone nucleus is linked to another biologically active moiety.Semicarbazide/Thiosemicarbazide was reacted with b e n z o y l chloride to obtain N-hydrazinocarbonyl benzene-1-carboxamide/N-hydrazinocarbothioylbenzene-1 carboxamide respectively.These were then condensed with various aldehydes to yield the intermediate Schiff bases. Thiazolidin-4-ones were prepared by the reaction of Schiff bases with mercaptoacetic acid in dry benzene by refluxing for 16-18 hours. The purity of the compounds synthesized was established by TLC.The synthesiz ed derivatives were characteriz ed by FT-IR, 1HNMR and Mass spectral analysis. All the derivatives synthesized were screened for their anti-bacterial and antifungal activities using cup-plate method against Bacillus subtilis, Salmonella typhi, Escherichia coli, Staphylococcus aureus, Aspergillus niger and Candida albicans at 100µ g/ml using ciprofloxacin and clotrimazole as reference standard drugs respectively.The compounds belonging to series (3A1-3A6) have shown promising antibacterial and antifungal activity and those belonging to series (3B1-3B6) were moderate compared to standard. The antimicrobial activity data reveals that, the compounds bearing the phenyl carbonyl urea in their structure, were found to be more potent than the phenyl carbonyl thiourea containing derivatives, indicating the influence of oxygen in enhancing the antimicrobial potency. Keywords: Schif bases,Thiazolidin-4-one,Antimicrobia
