AbstractThe hybrid nanoparticles of nickel and copper oxide are optimized by varying synthetic conditions such as precursor salt concentration, rate of reagent addition, pH, and temperature. The resulting nanoparticles are characterized by using UV‐Visible and fluorescence spectroscopy, hydrodynamic size, zeta potential, polydispersity index, SEM, EDX, XRD, and FTIR spectroscopy. The control over composition and physical properties of these hybrid oxides are analyzed through careful variations in the synthetic parameters. UV‐Vis analysis demonstrated the successful synthesis of NiO‐CuO hybrid nanoparticles at various concentrations. NiO dominant hybrids are obtained by quick addition of the reagent and at higher pH, while CuO dominant hybrids require slower addition of reagent and lower pH. The increase in the temperature causes a hypochromic shift in the UV‐Vis absorption, whereas fluorescence is enhanced with increase in the CuO concentration. The fluorescence generally remained stable by varying time of reagent addition, pH, and temperature. More stable and least‐sized NiO‐CuO hybrid nanoparticles are obtained at ratios of 75 : 25 and 25 : 75, by quick addition of reagent, at higher pH levels, and at higher temperatures. A better understanding of their physical and optical properties obtained by varying synthetic parameters may potentially result in their enhanced applications.