Two-dimensional (2D) metal organic framework (MOP) nanosheets are attracting increasing research interest. Here, for the first time, we report the facile synthesis of 2D porphyrin paddlewheel framework-3 (PPF-3) MOF nanosheets with thickness of ca. 12-43 nm. Through the simultaneous sulfidation and carbonization of PPF-3 MOF nanosheets, we have prepared the nanocomposite of CoS1.097 nanoparticles (NPs) and nitrogen-doped carbon, referred to as CoSNC, in which the CoS1.097 NPs with size of ca. 10 nm are embedded in the nitrogen-doped carbon matrix. As a proof-of-concept application, the obtained 2D CoSNC nanocomposite is used as an electrode material for a supercapacitor, exhibits a specific capacitance of 360.1 F g(-1) at a current density of 1.5 A g(-1). Moreover, the composite electrode also shows high rate capability. Its specific capacitance delivered at a current density of 30.0 A g(-1) retains 56.8% of the value at 1.5 A g(-1).