Zinc oxide nanoparticles were synthesized through wet chemical method. Polyaniline was synthesized by oxidative polymerization of aniline using potassium perdisulphate as oxidizing agent. Polyaniline -Zinc oxide nanocomposites were prepared by five different percentages of zinc oxide nanoparticles mixed with synthesized polyaniline. The prepared metal oxide, polymer and Nano composites were characterized by UV–Vis, FT-IR, AFM and electrochemical studies. The FT-IR spectral studies indicated the presence of metal oxide and polymer in Nano composites. From the FT-IR spectra of Nano composites, the peak around 464 cm−1 indicated the bonding between Zn and O, the peak around 1573 cm−1 and 1503 cm−1 due to stretching vibrations of the quinonoid and benzenoid rings of polyaniline respectively. The surface morphology was characterized by AFM. The UV–Vis spectrum of polyaniline was observed five absorption bands around 230 nm, 258 nm, 299 nm, 457 nm and 632 nm. Among these five bands, the absorption band around 299 nm is assigned to the π–π* transition of the phenyl ring and another band at 632 nm is assigned to the polaron n–π* transition. The UV–vis spectral absorption intensity of Nano composites was increased as increasing of zinc oxide incorporation in polyaniline. Cyclic Voltammetric studies exhibit good sensitivity response at pH 1.0. Chronoamperometric and Chronocoulometric studies were also carried out for polymer–metal oxide nanocomposites. The present study especially aims to investigate PAni-ZnO Nano composites in order to obtain a new noble material which can be utilized for solar cell applications.