Benzoxazine-derived porous nitrogen self-doped carbon aerogels with ultralight and good yield can be prepared by direct polymerization of trifunctional benzoxazine monomer in the catalysis of concentrated hydrochloric acid.This allows for significantly widened density range(0.8-4.5 mg cm-3)and avoiding any sacrificial etching.When serving as electrode materials for supercapacitors,the resulting hierarchical porous carbon aerogels shows ultrahigh specific capacitance,excellent rate performance and good cycling stability(retention of 97.3%even after 10000 continuous charge-discharge cycles).Besides energy storage devices,the interconnected nanoporous carbon aerogels can also find applications in oil/water separation,heavy metals removal,catalyst supports,and so forth.