AbstractThe polymerization of isobutene with VOCl3in heptane was investigated. In contrast to reports in the literature, the polymerization only starts upon irradiation with light, also when naphthalene is added, and it ceases when the light source is switched off. Thus, it is suggested that the reaction proceeds like a photoinitiated cationic polymerization, and the claim of a living system is not corroborated.