A low-cost 1D cobalt-based coordination polymer (CP) [Co(BGPD)(DMSO)₂(H₂O)₂] (Co-BD; H₂BGPD=N, N'-bis(glycinyl)pyromellitic diimide; DMSO=dimethyl sulfoxide) was synthesized by a simple method, and its crystal structure was characterized. In a three-electrode system, Co-BD, as the electrode material for supercapacitors, achieved a specific capacitance of 830 F·g^-1 at 1 A·g^-1, equivalent to a specific capacity of 116.4 mAh·g^-1, and exhibited high-rate capability, reaching 212 F·g^-1 at 20 A·g^-1. Impressively, Co-BD||rGO (reduced graphene oxide), representing an asymmetrical supercapacitor, owns a higher energy density of 14.2 Wh·kg^-1 at 0.80 kW·kg^-1, and an excellent cycle performance (After 4 000 cycles at 1 A·g^-1, the capacitance retention was up to 94%).