CuSe-gCN nanocrystals were premeditated and produced utilizing a simple hydrothermal method. Different analytical techniques well characterized the generated samples. The prepared samples also contain nanocrystals with a vertical shape, decorated with numerous nanoparticles. All characterizations confirm the phase composition of composite CuSe-gCN. The pore size of the N2 adsorption-desorption isotherm also pointed to a mesoporous structure. Furthermore, the combination of distinct morphology nanoparticles embellished on gCN graphitized nanotubes helps to achieve larger current densities and lower starting potentials for the oxygen evolution process. Because of their unique mesoporous structure, the CuSe-gCN catalysts show exceptional electrical conductivity and electrocatalytic activity. Compared to monometallic CuSe and gCN, CuSe-gCN significantly lower overpotential of 208 mV was needed to obtain a current density of 10 mA/cm2. The CuSe-gCN nanocrystals displayed good stability and a low Tafel slope of 35 mV/dec. This research shows that it is possible to use a copper-based selenide with gCN and combine all the beneficial characteristics in a single catalyst system.. Still, it also offers fresh perspectives on the logical proposal and creation of effective electrocatalysts for various applications.