The 1-[1,8-bis(dimethylamino)-4-naphthyl]ethyl carbocation generated from the corresponding alcohol in benzene in the presence of Al2O3 undergoes elimination according to the El mechanism to give previously unknown 1,8-bis(dimethylamino)-4-vinylnaphthalene in a good yield: This compound was also synthesized from 1,8-bis(dimethylamino)4-formylnaphthalene by the Wittig reaction. Polymerization of the vinylic derivative obtained was studied.