The acetyl benzo[f]coumarin condensed with phenyl hydrazine to afford the corresponding phenyl hydra
zone which cyclized into the pyrazolyl benzocoumarin under Vilsmeier reaction conditions. The pyrazolyla
ldehyde was used as starting material for synthesis of other heterocyclic compounds containing pyrazolylben
zocoumarin moiety. The ethyl benzo[f]coumarin carboxylate were subjected to react with other reagents to
synthesize thiazolidinyl and oxadiazolyl derivatives attached to benzocoumarin system. Some of novel syn
thesized compounds showed highly antibacterial and antifungal activities.