A simple and efficient method has been described for the synthesis of 9,9-Dimethyl-12-phenyl- 9,10-dihydro-8H-benzo [a] xanthen-11(12H)-one derivatives from aromatic aldehydes, β- naphthol and 5,5-dimethylcyclohexane-1,3-dione using a mild phenylboronic acid as a catalyst in good yields.