The anti-microbial action of benzimidazole of ampicillin, was examined in Vitro beneath a specific conditions, utilizing the disc diffusion method, against different gram-positive and gram-negative pathogenic microorganisms such as Bacillus cereus, Staphylococcus aureus Pseudomonas aeruginosa and Escherichia Coli. An arrangement of these compounds were arranged and have appeared to hinder phthogenic development, the range of the zone of restraint. The zone of Obstacles of compounds founds from 7 mm2 to 46 mm2 Among the synthesized compounds in common. 6-Methoxy-N-phenyl- 1H-benzo [d]imidazol-2-amine(1c, zone of inhibition 9 mm2 at 40 µg/ml against Escherichia coli ) and 6-Chloro-N-phenyl-1H-benzo [d]imidazol-2-amine (1d, zone of inhibition 18 mm2 at 40 µg/ml against Bacillus cereus) have appeared great movement. While 1j, zone of inhibition 20 mm2 at 40 µg/ml), and (1i, zone of inhibition 20 mm2 at 40 µg/ml) were found to be displayed directly to great action against Bacillus cereus and Escherichia coli. 1p did not appear any movement against Staphylococcus aureus .1e did not appear any movement against Escherichia Coli and Staphylococcus aureus.The results have shown clearly that the contribution of el ectron -donation and electron- withdrawal to the aromatic ring i ncreases antibacterial activity. Target benzimidazolessamples sho wed antibacterial & reference antibiotic ampicillin in vitro.