In present paper , we report the organic syntheses of four compounds from 7-Chloro-4-hydroxy-chromen-2-one and describe the results of antibacterial activity of purified compounds as 4,7-Dichloro-chromen-2-one (1a), 7-chloro-4- (4-chloro-phenylamino)-chromen-2-one(2a),[4-(4-chloro-phenylamiono)-2-oxo-2H-chromen-7-ylamino]-acetic acid (3a), have been synthesized and characterized using melting points, IR spectra, 1H-NMR and 13C-NMR spectra. The antibacterial activity of synthesized compounds and streptomycin and cefalexine at concentrations of 2mg/ml, 3mg/ml and 5mg/ml, have been evaluated against three strains of bacterial culture; Staphylococcus aureus, E.coli and Bacillus cereus. The compounds show bacteriostatic and bactericidal activity.