A series of hierarchically structured porous polyureas are prepared through the polymerization of diisocyanate monomers and H2O via a one-step and template-free strategy. This simple archetypal reaction combines carbon dioxide foaming process and hyper-crosslinking reaction. The obtained hierarchically porous polyureas (HPUs) consist of micro- and mesopores created by hyper-crosslinking reaction, and macropores generated by carbon dioxide foaming process. The HPUs have a high surface area up to 483.3 m(2)/g, and large pore volume (0.76 cm(3)/g). Besides, the nitrogen-doped carbon materials prepared by pyrolyzing the HPUs show a high specific capacitance (209 Fig at 1.0 A/g) and good cycling stability (99.8% capacitance retention after 5000 cycles), demonstrating the advantages of the hierarchically porous structure and nitrogen-rich chemical composition of HPUs. (C) 2016 Published by Elsevier Ltd.