The nanocomposites samples are made using the polymerization fabrication method to prepare the films consisting of iron III oxide (Fe2O3) and poly-4-chloroaniline P(4ClAni). The samples were characterized using the energy dispersive X-ray (EDX), X-ray diffraction (XRD), photoluminescence (PL) and Transmission electron microscope (TEM) to indicate the nanocomposites P(4ClAni)/Fe2O3 films were successfully fabricated. The EDX analysis confirmed the predicted chemical composition of P(4ClAni)/Fe2O3. The TEM showed spherical nanoparticles of Fe2O3 with approximately homogeneously and uniform sizes in between 30 and 40 nm. The effect of Fe2O3 on optical properties in wavelength range of 190 nm to 1200 nm has been recorded. The dispersion energy values for P(4ClAni) were found to be 0.72 eV increased to 0.81 eV, 0.96 eV and 1.21 eV, respectively, when the concentration of Fe2O3 increased from 3% to 6% and 9%. The relaxation time decrease from 4.46×10−6 s to 3.52×10−6 s as the concentration of Fe2O3 increases from 3% to 9%. Strong interactions between P(4ClAni) and Fe2O3 were supported by the obtained results of this work. The obtained data investigate the prepared P(4ClAni)/Fe2O3 nanocomposites can be applied in several areas of optoelectronics.