With 4,4 '-diaminodiphenylmethane as the starting material, a compound (M1) containing two functional isocyanide groups was successfully prepared via Hofmann method, and a polyisocyanide derivative (P1), with a cross-linked structure, was successfully prepared via Ni2+-catalyzed polymerization. Electrochemical detection of nitrite was achieved by utilizing P1-modified glassy carbon electrode as the working electrode, and the corresponding detection limit reached ~ 0.51 mu M (3 sigma/k). Subsequently, nitrogen-doped porous carbon material (P1-C) was obtained by direct carbonization of P1. The preliminary study of its electrochemical performance was carried out. Specific capacitance of P1-C reached 152.5 F g(-1) at 0.5 A g(-1), and high capacitance retention of 94.4% was recorded after 1000 galvanostatic charge-discharge cycles (at 1 A g(-1)), indicating that P1-C can act as potential energy storage electrode material.