1H-Cyclopropa[b]naphthalene (10a) and 3-methyl or dimethyl derivatives have been synthesized by interception of appropriately substituted o-quinodimethanes 3 with 1-bromo-2-chlorocyclopropene 5, and subsequent dehydrohalogenation of the adducts. The o-quinodimethane derivatives 3 in turn were obtained from the diynes 7via base-induced isomerization to bisallenes 8 and thermal electrocyclic ring closure.