A method of the synthesis of oligocarbonate diols from five-membered cyclic carbonates and aliphatic diols using azeotropic solvents is presented. The influence of a catalyst and reaction conditions on the alkylene oxide acid alkylene carbonate insertion into macrodiol molecules were studied and the reaction mechanism is discussed. The oligomeric products were analyzed by means of MALDI-TOF mass spectrometry. The transesterification reaction between propylene carbonate and diols containing six or more carbon atoms in a molecule carried out in the presence of the coordination catalysts such as tin or zinc carboxylate leads to almost pure oligocarbonate diols.