In present paper , we report the organic syntheses of four compounds from 4,7-Dihydroxy-chromen-2-one and describe the results of antibacterial activity of purified compounds. Compounds 4,7-Dichloro-2- oxo-2H-chromene- 3-carbaldehyde (1a). 4,7-Dichloro –chromen -2-one (2a) , 4,7-Dichloro -3- iminomethyl-chromen-2-one (3a), 3- Iminomethyl -4,7-bis –(4-methoxy-phenylamino ) – chromen-2-one ( 4a), 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.