Synthesis of five 2-aryl-3-hydroxythieno[2,3-b]quinoline 1,1-dioxides (38-42) from 3-formylquinoline-2-thiol ( 3 ) via a facile oxidation-cyclization sequence is reported. Reaction of appropriate benzyl chlorides with the thiol ( 3 ) in the presence of sodium methoxide gave excellent yields of the corresponding benzyl 2-(3-formylquinolyl) sulfides (4-8) . Direct oxidation of these sulfides to the corresponding sulfones (23-27) was effected with excess sodium chlorite in aqueous pyridine. Esterification of these sulfone-acids followed by brief treatment of the resulting esters 28-32 with sodium methoxide gave the desired compounds 38-42 after acidification. The benzyl 2-(3-formylquinolyl) sulfides were also selectively oxidized to the corresponding sulfoxides (13-17) . Thus sodium chlorite has proved to be an effective reagent for the stepwise oxidation of sulfides to sulfones. The title compounds were potent inhibitors of cyclic AMP phosphodiesterase, but failed to display significant antiinflammatory effects in the carrageenan rat paw edema test or significant activity in the phenylquinone induced writhing test for analgesia.