2-Methoxyquinoline 3, 4-quinodimethane 4, X= OMe, can be generrated from the quinoline 3, 4-fused dihydrothiophene S, S-dioxide 23 and trapped with dienophiles but 4- methoxyquinoline 2, 3-quinodimethane 3, X= OMe, cannot be obtained from the corresponding sulfone. Quinolone 2, 3-and 3, 4-quinodimethanes are readily available from the sulfones 9 and 19 respectively