In this present work, the pristine and the different percentages of co-doped NiO nanoparticles have been successfully synthesized through the sol-gel method. The X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), UV-Visible spectroscopy (UV-Vis), Fourier Transform Infra-Red Spectroscopy (FT-IR), and Vibrating Sample Magnetometer (VSM) were used to study the structural, morphological, optical, functional, and magnetic properties of the synthesized materials. The XRD patterns confirmed the formation of cubic phased NiO with their crystallite size, microstrain, dislocation density was estimated, and the average crystallite size increased with co-dopant inclusion. By introducing the co-dopant proportion in NiO lattice, the intensity of optical absorption was found to increase and the optical bandgap decreased from (E g = 3.6, 3.54, 3.50 eV) due to quantum size effect. SEM result exhibits that the particles are spherical-shaped morphology. The VSM examination shows the magnetic transition of soft to hard-ferromagnetism in room temperature on Zn, Mn codopant ions occupying Ni translational symmetry.