Alternated PHUs were synthesized by reacting 0.5 eq. of amine Aj, where j = 1 or 2, with the in-situ generated BisCC-XAi , where X = E or T, i = 1 or 2 and i ≠ j. Reactions were carried out at 80 °C for a period of 20 h. In all cases, the reaction is brought close to completion (conversions are reported in Table ). The resulting polymers are expected to contain the repeating unit diHU-Ai-diHU-Aj (cf. Figure ). They are noted poly(XAi-alt-XAj), where X stands for the vicinal dicarbonate used in step 1, Ai the amine used in step 1 and Aj the amine used in step 2.