Hetero cyclic compounds were the major class of organic compounds used as anti-microbial agent. The synthesis of coumarin and their derivatives via different routes were reported, Pechmann condensation was wide used. The aims to review the reported work including synthesis and anti-microbial properties was to introduce the researcher with synthetic routes and microbial importance of coumarins. The review suggested that, coumarin and their derivatives were prominent anti-microbial agents.