Various benzo-and dibenzoannelated cycloheptatrienylidenes (cycloheptatetraenes) have been generated in methanol and ethanol by alkoxide-induced dehydrochlorination of chlorocycloheptatrienes and, where applicable, by photolysis of tosylhydrazone sodium salts. 1, 2-and 3, 4benzoannelated systems (19, 20 and 28, 29) give identical mixtures of allyl ethers (23, 25) arising from the benzotropylium ion 24. Formation of 24 and of vinyl ...