A series of new 3-(4-(p-toluidino)thiazol-2-yl)-2-phenylthiazolidin-4-one derivatives (5a-g) were synthesized from novel schiff base of 2-((4-(p-toluidino)thiazol-2-ylimino)methyl)phenol (4a-g) with thioglycolic acid in presence of anhydrous zinc chloride. The chemical structures of these compounds were confirmed by various physic-chemical methods viz, IR, 1H NMR, mass spectral data and elemental analysis. Newly synthesized compounds were screened in vitro for their antimicrobial activity against varieties of gram +ve and gram -ve bacterial strains such as Bacillus subtilis, Pseudomonas aeruginosa and fungi strain Candida albicans & Aspergillus nigar at 40 μg/mL. The chloro and bromo substituted 2,3-substituted thiazolidin-4-one derivatives are showing activity as compare to the other functional groups.