In conclusion, we have deeply explained the high reactivity of vicinal dicarbonates (EDC and TDC) and demonstrated that this reactivity is highly suitable for the synthesis of well-defined novel di(hydroxy-urethane) dicarbonates (BisCC) in soft experimental conditions (25°C, ambient atmosphere, 4h). The selectivity of the hydroxyl group obtained during the ring opening reaction of cyclic carbonate is dictated by the spatial configuration of EDC and TDC. BisCC2 with (OH)II-(OH)II groups are obtained from two diamines under the same experimental condition and with similar selectivity. This result opens the possibility to design a new platform of bio-based 5CCs. Moreover, macromolecular engineering allows the creation of regioregular PHUs, with tuneable and controllable properties, using sustainable products, such as sugar derivative tetraols. A broad range of properties can be obtained from erythritol and threitolbased PHUs, by a very simple selection of diamines and vicinal 5CCs. These simple way of synthesis of poly(hydroxy-urethane)s is promising in order to obtain green and functional polymers at low cost to respond to nowadays challenges.