Synthetic studies of fused pyrimidine have been reported extensively because of their structural diversity and association with a wide spectrum of biological activity. It has been observed over the years that poly substituted pyrimido[1,2-a]benzimidazoles possess a wide spectrum of biological activities and they are structurally related to natural purine bases. With this background we have prepared a library of imidazopyrimidine analogues by one pot Biginelly type multi-component reaction. The process has several advantages like neat reaction and easy workup and purification steps. All the synthesized compounds were evaluated for their antimicrobial activity. The investigation of antimicrobial and anti-fungal screening data revealed that all the tested compounds showed moderate to significant activity.