We developed 3-D network carbon materials by directly pyrolyzing as-prepared polynaphthalene (PNT). The PNT-based materials were synthesized from chloromethylated naphthalene and were self-polymerized using anhydrous aluminum chloride as the Friedel-Crafts catalyst and chloromethyl methyl ether as a crosslinker. The micro-, meso-, and macroporous 3-D carbon materials showed large specific surface areas, large electrolyte-electrode interface areas, and continuous electron transport paths. MnO2/carbon composites were then synthesized by chemically depositing MnO2 onto the carbon substrate surfaces through a self-limiting redox reaction between KMnO4 solution and carbon substrates, producing high-performance pseudo-capacitor electrodes. The unique electrode architecture demonstrated high capacitance up to 286.8 F g-1, and good cycling stability up to 1000 cycles without losing its capacitance. The electrode shows potential applications for the development of high-performance supercapacitors for a variety of power-demanding devices.