An efficient, simple clean synthesis of Schiff bases of some 4-nitroaniline/ 2,4-dinitroaniline/ 3,4-dichloroaniline / 4-methoxy-3-nitro aniline with 3-bromo-4-fluorobenzaldehyde were done by an ultrasound irradiation method. The major advantages of ultra-sonication are short reaction time, operational simplicity, high yield, easy workup and environment friendly procedure. The isolated compounds obtained by ultrasound irradiation method were characterized by UV, IR and NMR spectral data. These acoustical parameters were determined. Furthermore their antibacterial activities are screened against certain strains of bacteria and showed significant anti-microbial activity.