Interfacial polycondensation of bisphenol-A and phosgene is a well-known way to prepare bisphenol-A polycarbonate, the molecular weight of which can be controlled by the addition of suitable amounts of phenol. When the chain stopper is a bifunctional compound, the way is open to the synthesis of telechelic polycarbonates. 4-Hydroxybenzoic acid, 4-hydroxybenzenesulfonic acid, 4 N,N′-dimethylaminophenol and the iodoammonium derivative have been used as bifunctional chain stoppers in the synthesis of acid and amino telechelic polycarbonates. The n.m.r. analysis of the final products has provided evidence for the successful synthesis of α,ω-tertiary amino and α,ω-quaternary ammonium polycarbonates. In contrast, fast transesterification reactions prevent α,ω-carboxylic and sulfonic acid polycarbonate from being prepared in a controlled way.