Abstract <p>An uncomplicated and cost-effective sol–gel method was employed to effectively synthesize nickel oxide nanoparticles at various pH levels. A range of analytical instruments is utilized to define the material’s structural, morphological, optical, dielectric, magnetic, and electrochemical characteristics. The tools comprise X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, photoluminescence spectroscopy (PL), LCZ measurements, and the vibrating sample magnetometer (VSM). Analysis of the powder XRD pattern enabled us to ascertain the crystallite size of the synthesized powder, revealing that the crystallite dimensions increase with elevated pH levels. An elevation in pH level influences the enhancement of the strain value, as demonstrated in the W–H plot. The influence of pH levels on morphological alterations was confirmed by scanning electron micrographs. As pH levels increase, blue shift absorption peaks are observed in the UV-visible spectra. Estimates of the bandgap value were obtained utilizing the Mott and Davis connection, which demonstrates that the bandgap value escalates with rising pH levels. The correlation between temperature and both the dielectric constant and dielectric loss is analyzed within the frequency spectrum of 50 Hz to 5 MHz. The grain effect, as indicated by the Cole–Cole plot, has been eclipsed by the influences at the grain boundary and the interfacial effects in all synthetic materials. Nickel oxide nanoparticles exhibited ferromagnetic properties over a range of pH values. For the NiO sample, the values of squareness and magnetization are enhanced when the pH is set at 8.0 during synthesis. The el-ectrochemical study validated that the NiO sample generated at pH level 8.0 had an improved conductivity property.</p>