The synthesis of sym. and asym. telechelic polyisobutylenes (PIBs) is reported. A PIB with a primary hydroxy head group and an allyl end group (HO-PIB-Allyl, Mn = 4300 g/mol, Mw/Mn = 1.2) was synthesized by living carbocationic polymn. of isobutylene (IB) using propylene epoxide as an initiator and allyltrimethylsilane as a terminating agent. Thiol-ene click chem. using 2-mercaptoethanol and 1,2-ethanedithiol yielded an asym. HO-PIB-SEt-OH (Mn = 4646 g/mol, Mw/Mn = 1.18) and a sym. HO-PIB-OH (Mn = 8594 g/mol, Mw/Mn = 1.2), resp. A sym. allyl telechelic PIB (Mn = 8669 g/mol, Mw/Mn = 1.2) was prepd. by enzymic transesterification of divinyl adipate with the primary hydroxy group of HO-PIB-Allyl.