<p>A magnetic Fe₃O₄/MoO₃/CuO nanocomposite (NC) has been prepared via a facile method and used to decompose Methylene Blue and Rhodamine B dyes. The morphology and optical properties of the magnetic NC were obtained by using DRS, XRD, FE-SEM, EDS, TEM, and VSM techniques. Based on the FE-SEM and TEM analysis, the spherical morphology of the Fe₃O₄/MoO₃/CuO NC was identified. Additionally, the band gap energy of the Fe₃O₄/MoO₃/CuO NC was determined, and the absorption wavelength extended into the visible region, as evidenced by the DRS results. Based on the DRS analysis, the bandgap value of Fe₃O₄/MoO₃/CuO NC was equal to 2.8&#xa0;eV. The low-cost and high-reactive Fe₃O₄/MoO₃/CuO NC was applied for dye degradation as a photocatalyst under sunlight. At the end of the reaction, the NC was readily separated using an external magnetic field and recycled five times without a significant decrease in photocatalytic activity. The degradation percentages of the color solution in presence of Fe₃O₄/MoO₃/CuO NC were achieved to 96% and 91% for MB and RhB, respectively. Moreover, the reusability of the photocatalyst over 5 cycles showing no significant reduction in dye degradation efficiency, indicating its suitability as a photocatalyst for dye degradation. This research demonstrates the Fe₃O₄/MoO₃/CuO NC as a highly efficient and environmentally friendly photocatalytic for the treatment of dye.</p> Graphical abstract <p></p>