Synthesis of nanoparticles in the nanotechnology research field, which enhances the development of eco-friendly methods. Chemical co– precipitation method is used for the synthesis of MnO nanoparticles were annealed the precursor, by operating under Muffle Furnace, have been synthesized with the help of salt such as manganese acetate by using NaOH solution. The optical analysis measured by UV–VISIBLE spectroscopy, showed that the optical properties of the nanoparticles were analyzed, the absorption peak at 328 nm and UV–visible spectrum exhibited the prominent absorption. Particle size and morphology analysis carried by Scanning Electron Microscopy (SEM) showed that open and semi linear structures. Elemental composition measured by Energy Dispersive Analysis (EDX). Hexagonal structures were carried out by using High Resolution-Transmission Electron Microscopy (HR-TEM), exhibits pure single crystalline structures and SAED which confirms the purity of the synthesized sample. Manganese dioxide nanoparticles are one of the most attractive inorganic materials with high range of physical and chemical applications on it because of characteristic nature and its ease preparation, massive optical properties showed that it is eligible for application on photovoltaic cells.