AbstractThe synthesis of 1,1‐dichloro and 1,1‐difluoronaphtho[b]cyclopropenes 1 and 2 starting from 4,5‐dimethylenecyclohexene and tetrachloro‐ or 1,2‐dichloro‐3,3‐ difluorocyclopropene, respectively, is described. Both 1 and 2 ionize in cold fluorosulfonic acid to yield stable aromatic cations 3 and 4. Upon quenching with water, 1‐chloronaphtho[b]cyclopropenium ion 3 affords