The Cu1.5Mn1.5O4 compounds were synthesized via the sol-gel method and calcined 700 °C and 900 °C.XRD anal. revealed that the average particle sizes were within the nanoscale range (55-66 nm) and increased with increasing annealing temperaturesSEM images confirmed the formation of nearly spherical Cu1.5Mn1.5O4 particles with slight agglomeration, showing an increase in size as the annealing temperature rose.The optical properties of these compounds were investigated using IR (IR) and UV-Vis absorption spectroscopy.A theor. crystal-field anal. was realized from the UV-vis absorbance spectrum shows that some of the observed bands correspond to the d-d transitions of Mn4+ ions in the octahedral distorted within the Cu1.5Mn1.5O4 structure.DASF method revealed wide direct optical band gaps of 3.22 eV and 3.10 eV for the Cu1.5Mn1.5O4 compounds annealed at 700 °C and 900 °C, resp.The high Urbach energies, EU (0.895 eV, 0.804 eV), and the weak absorption tail energies, EWAT (1.637 eV, 1.159 eV), suggest a significant d. of localized states.Addnl., key optical parameters, including the absorption coefficient (α), optical conductivity (σop), dielec. constant (ε1), loss tangent (tan δ), and energy loss functions (Vel, Sel), were calculatedThe single-oscillator energy (E0), and dispersion energy (Ed) were analyzed using the Wemple and Di Domenico model.Results show that Cu1.5Mn1.5O4 samples exhibit excellent light absorption, low-loss tangent, high dielec. constant (ε1), refractive index, and optical conductivity over the solar spectrum.The refractive index (n) for the Cu1.5Mn1.5O4 compounds calcined at 900 °C ranged from 3.3 to 4.26.These findings highlight that Cu1.5Mn1.5O4 compounds are promising candidates for optoelectronic devices.