The casting method was employed for the preparation of polymer blend films doped with TiO2 (0.5, 1, 1.5, and 2.3 wt.%). The XRD outcomes show that TiO2 phase formation is anatase, with an average crystal size of 20.25 nm. PANI/PMMA-TiO2 nanocomposites samples have an amorphous nature. In addition, the degree of amorphousity is increased with the increase of the content of the TiO2 NPs. The FTIR method was employed for presenting the vibrational bands of the nanocomposites and the intermolecular bonding of the blend with the TiO2 NPs. The applied investigation involved the optical constant like absorption as well as t90-etransmission spectra, refractive index, reflectance, coefficient extinction, dielectric constant’ imaginary and real parts, the susceptibility (χ3) of third order and the optical band gaps. The optical band gap (Eg) values of the films of fabricated nanocomposites was lower upon doping (≤ 1.5 wt.%). The reduction of the value happened due to the introduction of the preselected TiO2 NPs into thin films. Such values significantly match the values which were revealed by the Tauc technique. It was proved through DSC and TGA techniques that TiO2 NPs can lead to the enhancement of the polymer blend in terms of thermal stability. As displayed by the DSC analysis, there is a single Tg of the polymer blend (PANI/PMMA), which prove their miscibility. The optical constants displayed by the experimental results show noticeable changes upon raising the doping concentrations. The resultant doped thin films indicate that the fabricating high-efficient optoelectronic machines are greatly promising.