The synthesis of nitrogen, boron, and nitrogen–boron-codoped graphenes was attained via mixing solutions of GO with urea, boric acid, and a mixture of both, respectively, followed by drying in vacuum and annealing at 900 °C for 10 h. These materials were thoroughly characterized employing XRD, TEM, FTIR, Raman, UV–vis, XPS, IPCE%, and electrical conductivity measurements. The nitrogen-doped graphene (NG) showed an excellent supercapacitor performance with a higher specific capacitance (388 F·g–1 at 1 A·g–1), superior stability, and a higher power density of 0.260 kW kg–1. This was mainly due to the designated N types of doping and most importantly N–O bonds and to lowering charge transfer and equivalent series resistances. The NG also indicated the highest photocatalytic performance for methylene blue (MB 20 ppm, power = 160 W, λ > 420 nm) and phenol (5 ppm) degradation under visible light.