Poly(hydroxyurethane-urea)s (PHUUs), which have complementary thermal and mechanical properties with poly(hydroxyurethane)s (PHUs) and polyureas, are of great potential for practical applications. Herein, several novel PHUUs were synthesized through polyaddition reaction from 5-membered dicyclic carbonates and amino-terminal polyurea oligomers, and corresponding PHUs were also synthesized as controls. It was worth noting that carbon dioxide was starting materials in the synthesis of both 5-membered dicyclic carbonates and amino-terminal polyurea oligomers. The structures and properties of PHUUs and PHUs were characterized by FTIR, 1H NMR, SEC, water contact angle measurement, TGA, DSC, and tensile test. The urethane-to-urea ratio of PHUUs depended on the diamines used in the synthesis of amino-terminal polyurea oligomers. With the introduction of urea moieties, PHUUs exhibited improved surface hydrophobicity and thermal properties. Meanwhile, the introduction of urea moieties and the structure of selected diamine influenced glass transition temperature (Tg) and mechanical properties of PHUUs. This work offered a fascinating option for preparing PHUUs and might contribute to tackling climate change.