The citrate approach was employed to successfully synthesize Mn0.4Zn0.6−xCuxFe2O4 (MZCF) with a nanostructured shape. A thorough examination was conducted on the microstructural, magnetic, and optical properties of the nanoparticles obtained. The X-ray diffraction (XRD) patterns revealed that all of the compositions exhibit a high degree of single-phase spinel formation. The experimental findings indicate that the introduction of copper ions leads to a reduction in both lattice constant and porosity, while concurrently resulting in an increase in the theoretical X-ray and bulk densities. The analysis of UV–Vis spectroscopy indicated that MZCF exhibited a direct band gap falling within the range of 1.61–1.78 eV. The magnetic characteristics were assessed through the analysis of hysteresis plots. The introduction of copper (Cu) content leads to notable improvements in the saturation (Ms) and remanent magnetization (Mr) values, which range from 40.21 to 58.78 and 4.46–10.54 emu/g, respectively. The assessment of the microwave frequency response has verified the appropriateness of MZCF nanoferrites for application within the frequency spectrum spanning from 8 to 13 gigahertz. The nanoparticles exhibit improved magnetic properties, suggesting their potential appropriateness for applications involving highfrequency microwave absorption and switching. Furthermore, the nanoparticles Mn0.4Zn0.6Fe2O4 and Mn0.4Zn0.2Cu0.4Fe2O4 were subjected to analysis utilizing a solar light simulator in order to induce degradation of MB dye.