The action of potassium t-butoxide in diglyme on trans, anti, trans-and trans, syn, trans-1, 2, 5, 6-tetrabromocyclo-octane and on cyclo-octatetraene was found to produce benzocyclobutene, styrene, cyclo-octa-1, 3, 5-triene, and ethylbenzene. Similar base treatment of 1, 2, 5, 6, 9, 10-hexabromocyclododecane gave the hitherto unknown 1, 2- benzocyclo-octa-1, 3, 5-triene while 1, 2, 5, 6-tetrabromocyclododecane produced 1, 2- ...