The present work outlines the synthesis of prismatic shaped zinc oxide (ZnO) nanostructures through microwave combustion method using different microwave power (160, 320, 480, 640, and 800 W) using Zinc nitrate as a precursor and ethylene glycol as solvent. The structural characterization of the synthesized ZnO nanostructures has been accessed by X-ray diffraction study (XRD), Field emission scanning electron microscopy (FE–SEM), UV-Visible spectroscopy (UV-Vis), energy-dispersive analysis using X-rays (EDAX) and photoconductivity technique. The XRD and FE–SEM results confirmed that the crystal size and growth of ZnO nanostructures depended on the heating of microwave powers. EDAX shows the existence of Zn and O in the synthesized ZnO microstructures. The optical properties and band gap studies were undertaken by UV-Visible spectroscopy. I–V characterization study was performed to determine the electrical property of ZnO films.