Anhydride terminated polyisobutylene (PIB) oligomers were synthesized in a one- or two-step process from chlorine terminated oligomers. In the one-step process, chlorine functional oligomers were just heated in the presence of maleic anhydride (MA) for 12 h at 190-degrees-C without a catalyst. In the two-step process, the chlorine end functional groups were first converted by selective dehydrochlorination to isopropenylpoly-isobutylene end groups with t-BuOK in refluxing tetrahydrofuran during 16 h. In a second step, MA was coupled to the PIB with unsaturated end groups by reacting the oligomer with MA for 12 h at 190-degrees-C. These reactions could be followed by i.r. and n.m.r. The PIB-MA obtained had a functionality between 30% and 100%. In order to study the formation of amine functionalities, the PIB-MA was reacted with diamines. The coupling gave an imide bonding.