Department of Chemistry, Osmania University, Hyderabad-500 007 Manuscript received 5 July 1985, revised 14 February 1986, accepted 26 November 1986 A synthesis of 4,5-dihydroxy-3-p-benzoquinonylcoumarin is described involving condensation of 4,5-dihydroxycoumarin with p-benzoquinone. Subsequent Thiele's acetylation/reductive acetylation offered acetoxy-3-aryl-4-acetoxycouwarin which on hydrolysis gave the corresponding hydroxylated 3-aryl-4-hydroxycoumarins. The struc­tures of these products have been established by spectral data. Antibacterial and antifungal activities of these compounds are discussed.