A series of 1-cyclopropyl-6-flouro-1,4-dihydro-4-oxo-7-[4′-(p-nitro benzoyl) piperazin-1′-yl]-3-[N4-[N1-(p-substituted phenyl) sulfonamido] carbonyl] quinolines IVa-m and 1-cyclopropyl-6-fluoro-1,4- dihydro-4-oxo-7-[4′-(p-nitrobenzoyl) piperazin-1′-yl]-3-[N- (4″-substituted benzene sulfonamido)] carbonyl quinolines IVn&o have been prepared. Antibacterial activity against four different strains viz. two Gram positive bacteria Staphylococcus aureus, Bacillus subtilis and two Gram negative bacteria Escherichia coli, Psudomonus aeruginosa and two fungi Candida albicans and Candida geortichum have been carried out.