In this article, the synthesis, optical, and electrical properties of composites consisting of polyethylene oxide (PEO), carboxymethyl cellulose (CMC), and titanium dioxide nanoparticles are examined. Flexible nanocomposite samples comprising PEO, CMC, and TiO nanoparticles were produced swiftly via using the cast synthesis method. In addition, XRD and FT-IR analysis were performed in order to analyze the structures of the prepared samples. Our results demonstrate the PEO/CMC blend's effectiveness in interacting with TiO nanoparticles. The optical properties of the PEO/CMC and nanocomposite samples, such as the energy band gap, were studied using the UV/Vis optical absorbance. It was found that as TiO NP weight fraction increases, the energy gap narrows. Moreover, TiO nanoparticles with an average size of 16 nm were formed in spherical and rod shapes, according to a TEM image. The SEM images demonstrate how the distribution of TiO NPs increased upon the surfaces of the prepared films. The antibacterial activity in the nanocomposites was shown to be enhanced by the TiO NP concentrations. Finally, we proposed that PEO/CMC-0.8 wt. % TiO nanocomposites with enhanced optical, electrical, and dielectric properties should be used in electrochemical devices.