Llfluoranthene was accomplished through the intermediacy of 1, 12c-dihydrobenzo~] fluoranthen-3 (2H)-one. This ketone was converted to its a-phenylseleno derivative which underwent selenoxide elimination in basic hydrogen peroxide, forming benzo~] fluoranthene-2, 3-dione directly. In each synthesis reduction of the appropriate quinone with potassium borohydride afforded the desired dihydrodiol.