5-((1,3-dioxoisoindolin-2-yl)methyl)-2-hydroxy-N-(4-oxo-2-phenylthiazolidin-3-yl)benzamide (1a-h) undergoes facile condensation with aromatic aldehydes in the presence of sodium ethanolate to afford the corresponding N-(5-benzylidene-4-oxo-2-phenylthiazolidin-3-yl)-5-((1,3-dioxoisoindolin-2-yl)methyl)-2- hydroxybenzamide (2a-h) in good yields. These compounds (2a-h) on reaction with hydrazine, phenyl hydrazine and 4-chlorophenylhydrazine in sodium acetate and acetic acid gave appropriate pyrazole derivatives (3a-h), (4a-h) and (5a-h). The structures of these compounds were established on the basis of analytical data, 1H-NMR,13C-NMR and IR spectral data. All the newly synthesized compounds were evaluated for their antibacterial and antifungal activities. In summary, preliminary results indicate that some of the newly synthesized title compounds exhibited promising antibacterial activities and they warrant more consideration as prospective antimicrobials.