Two new types of pseudo-azulenes, thieno [3′,2′:5,6]thiopyrano[4,3-b]and thieno[3′,4′:5,6]thiopyrano[4,3-b]-indoles, and several benzo-derivatives thereof, have been synthesised by dehydrogenation of the indolisation products of arylhydrazones from 5,6-dihydrothieno[2,3-b]- and 5,6-dihydro-1,3-dimethylthieno[3,4-b]-thiopyran-4-one.