In Present work, the Reduction of ethyl 2-(4-phenyl substituted)-4-methylthiazole-5-carboxylate(1) by Lithium Aluminium hydride in diethyl ether Solvent yield (2-(4-phenyl substituted)-4-methylthiazol-5-yl) methanol (2) followed by Oxidation using IBX in the DMSO solvent, to yield 2-(4-phenyl substituted)-4- methylthiazole-5-carbaldehyde(3) which on further reaction with2-(4-phenyl substituted)-4-methylthiazole-5- carbohydrazide(4) in the presence of conc. sulphuric acid in ethanol solvent to yield N-((2-(4-phenyl substituted)- 4-methylthiazol-5-yl)methylene)-4-methyl-2-(phenyl substituted)thiazole-5-carbohydrazide(5) which further cyclisation with mercaptoacetic acid in presence of zinc chloride catalyst in DMF Solvent afforded series of thiazolidin-4-one derivatives namely N-(2-(2-(4-phenyl substituted)-4-methylthiazol-5-yl)-4-oxothiazolidin-3-yl)- 2-(4-phenyl substituted)-4-methyl thiazole-5-carboxamide(6a-h). The structure of all the synthesized compounds was characterized by FT-IR, 1H NMR, DIP MS data. Furthermore, compounds (6a-h) were screened for their antibacterial activity against gram negative (E. coli and P. aeruginosa) and gram positive (S. aureus and B. subtilis) bacteria, antifungal activity against pathogenic fungal strains and anti-inflammatory activities. Some of the compounds exhibited promising antibacterial, antifungal and anti-inflammatory activities.