A new series of 7-O-coumarinyl alkenoates were synthesized from 7-hydroxyl-coumarin and fatty acids using DCC and DMAP as catalyst. The synthesized compounds were characterized on the basis of their spectral data. All the target compounds were evaluated for their in vitro antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Streptococcus pyogene, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli and fungal cultures of Candida albicans, Candida krusei,Candida parapsilosis andCryptococcus neoformans. The minimum inhibitory concentration (MIC) was determined for the test compounds as well as for reference standards. Among the tested compounds, 7-O-coumarinyl (9Z, 12R)-12-hydroxyoctadec-9-enoate and 7-O-coumarinyl (12Z, 9R)-9-hydroxyoctadec-12-enoate showed the most potent antifungal as well as antibacterial activities.