Abstract The application of known methodology has provided 2, 3-dimethylidene-2, 3- dihydro-1, 4-benzodioxin (12) as the essential precursor for preparation of the cyclopropa- fused dibenzodioxin 3, 8-dioxa-1H-cyclopropa [b] anthracene (14). Cycloproparene (14) is both unstable and acid-sensitive, and readily dimerizes to a mixture of the dihydrotetraoxaheptacene (15) and its heptaphene analogue (16).
