A spongy black powder of LaCu0.25Mn0.75O3-δ was synthesized by a modified Pechini method in this study. Properties of LaCu0.25Mn0.75O3-δ perovskite were investigated via in situ Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction results indicated obtaining highly crystalline LaCu0.25Mn0.75O3-δ sample with crystallite size was 37 nm. FTIR results confirmed the formation of LaCu0.25Mn0.75O3-δnanoparticles. High-Resolution Transmission Electronic Microscope HRTEM image illustrates that the prepared sample is in the nanoscale with d-spacing equal to 0.13 nm matching the [440] plane of cubic LaCu0.25Mn0.75O3-δ.The optical properties of the obtained samples were investigated and indicated that the prepared sample is in the nanoscale.