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A new two-dimensional covalent organic framework (DBT-MA-COF) is designed and synthesized via Carbon–Nitrogen coupling reaction by using 2,5-dibromothiophene (DBT) and melamine (MA) as the monomers. The C−Hˑ N intralayer hydrogen bonding exists in the structure of DBT-MA-COF so that a plane rigid structure can be maintained. The material exhibits a quasi-reversible redox process caused by triazine units and the transformation of the quinone and aromatic structures to make the DBT-MA-COF possess pseudocapacitive characteristics. DBT-MA-COF has high heteroatom content for the existence of triazine and thiophene units, which can accelerate the transfer of electrolyte ions on the surface of DBT-MA-COF electrode and improve the solution conductivity of the material. The assembled asymmetric supercapacitor DBT-MA-COF//C-CTS ASC has a high energy density of 32.1 W h kg−1 with the power density of 800 W kg−1. The cycle life of the device is excellent which can reach 83% even after 30,000 continuous galvanostatic charge-discharge cycles. The strategy in this work provides a line of thinking to design and prepare new COFs used as long life and pseudocapacitive supercapacitor materials. Image 1 • A novel covalent organic framework(DBT-MA-COF) is synthesized via Carbon-Nitrogen coupling reaction. • C-H...N intralayer hydrogen bonding existed in DBT-MA-COF leads to a plane rigid structure. • The COF has pseudocapacitive characteristics for a transformation of quinone and aromatic structures in triazine unit. • The existence of triazine and thiophene units improves the conductivity of the resulting material. • Assembled asymmetric supercapacitor shows a high energy density of 32.1Wh kg-1 and the long life of 83% after 30000 cycles. [ABSTRACT FROM AUTHOR]