The chemistry which is used to peptide synthesis that replaces insoluble cross-linked resins with soluble polymer supports in a strategy termed as liquid-phase organic synthesis (LPOS).This advance recent approach has been modified sufficiently that reagents and catalyst are now being bound to soluble polymer supports for use in solution-phase combinatorial synthesis. Several different types of polymers have been investigated as supports in LPOS and also incorporated for the synthesis of peptide oligosaccharide and oligonucleotide synthesis. The most commonly used soluble polymer support is polyethylene glycol (PEG). The wide acceptability of PEG is directly linked to its broad solubility profile: soluble in dimethylformamide, dichloromethane, toluene, acetonitrile, water, and methanol .Coumarino benzimidazole derivatives were found to possess various activities which includes anti bacterial, anti protozoal , antifungal, anti inflammatory , anti allergic agents, anthelmentic activity , anti-parasitic activity, cytotoxicity and DNA topoisomerase I inhibitors activity . More ever many research groups have synthesized various benzimidazole compounds and tested for antiviral anti neoplastic and anti filarial agents.Based on these findings, we have synthesized various coumarino benzimidazole and screened for anti microbial activity. It was found that the derivatives S1, S2, S3 and S4 have shown significant antimicrobial activity against gram ve bacteria with zone of inhibition high as compared to S5 - S8 and the derivatives S1-S8 do not show any significant activity against gram +ve organism which shown in table no.1.
