Replacing toxic isocyanates and petro-based reactants currently employed for polyurethanes (PUs) synthesis is nowadays a major concern. Among all the possible routes to isocyanate-free PUs, aminolysis of cyclic carbonates, leading to polyhydroxyurethanes (PHUs) seems to be one of the most promising pathways. Herein, we discuss the added value brought by the reactive extrusion process on PHU synthesis. In order to evaluate the benefit and the versatility of the process, three different bis-cyclic carbonates exhibiting different reactivity (Diglycerol Dicarbonate, Seb-bCC-ester and one bisCC containing amide function, Und-6DA-bisCC), were tested in the course of polymerization with different diamines. The PHUs synthesized through reactive extrusion were then compared with the ones obtained through classical bulk polymerizations in terms of kinetics, PHU molar masses and side reactions, clearly demonstrating the benefit of the extrusion process.