A telechelic polymer or oligomer is a prepolymer capable of entering into further polymerization or other reactions through its reactive end-groups[1]. It can be used for example to synthesize block copolymers.By definition, a telechelic polymer is a di-end-functional polymer where both ends possess the same functionality.[2] Where the chain-ends of the polymer are not of the same functionality they are termed di-end-functional polymers.All polymers resulting from living polymerization are end-functional but may not necessarily be telechelic.[3]To prepare polymers by step-growth polymerization, telechelic polymers like polymeric diols and epoxy prepolymers can be used. The main examples are: Polyether diols; Polyester diols; Polycarbonate diols: Polyhexamethylene carbonate diol (PHMCD); Polyalcadiene diols: Hydroxyl-terminated polybutadiene (PBHT)...Other examples of telechelic polymers are the halato-telechelic polymers or halatopolymers[4]. The end-groups of these polymers are ionic or ionizable like carboxylate or quaternary ammonium groups.