A one-pot, two-step protocol for the direct synthesis of polyurethanes containing few carbonate linkages through polycondensation of diamines, dihalides, and CO, in the presence of Cs2CO3 and tetrabutylammonium bromide is described. The conditions were optimized by studying the polycondensation of CO, with 1,6-hexanediamine and 1,4-dibromobutane as model monomers. Then, various diamines and dihalides were tested under optimal conditions. Miscellaneous samples of such carbonate-containing polyurethanes exhibiting molar masses from 6000 to 22 000 g/mol (GPC) and yields higher than 85% were obtained. The thermal properties of such polyurethanes were unveiled by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA): they were found very similar to those of traditional polyurethanes obtained by diisocyanates + diols polycondensation.