Synthesis of novel benzo[4,5]imidazo[1,2-a]pyrimido[4,5-d] pyrimidines 5/6 has been achieved by reaction of 2-amino-4-aryl-4,10-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles 4 with formaldehyde/urea. The key intermediate 4, is obtained by reaction of 2-aminobenzaldehyde 1 with aromatic aldehyde and malononitrile by a three-component one-pot process. The newly synthesized title compounds 5/6 have been evaluated for their in vitro antimicrobial activity. Compounds 5 and 6 exhibit potent antimicrobial activity compared to that of standard drugs
