Redox or radical telomerizations of methyl 10-undecenoate (1) with different telogens such as CCl,, CC13Br, CCl,CF,, HPO(OEt), or different adducts of CCl, on vinylidene chloride and chlorotrifluoroethylene, were studied. Chemical transformation of the end of the chains led to the corresponding difunctional compounds. Starting with these last compounds, polycondensation reactions were carried out.