In this project, the prime focus was to synthesize zinc oxide nanoplates (ZnO-Nps) by a reliable, simple, and low cost facile hydrothermal method. Zinc acetate was used as major precursors; the synthesis was standardized in a 100 mL autoclave, at 180 °C for 24 h which results in nanoplates with 150–300 nm width and thickness 10–60 nm size and mesoporous nature with a specific surface area 126 cm2 g−1. The prepared sample was characterized by X-ray powder diffraction (XRPD), scaning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive microscopy (EDS), Fourior transfer infrared (FTIR) spectroscopy, X-ray photo electron microscopy (XPS), Brunauer–Emmett–Teller (BET), Photoluminance (PL), and Electrochemical impedance spectroscopy (EIS) techniques. For application purposes, photocatalytic and antimicrobial activities of ZnO-Nps were studied systematically. The material was made photo-active under visible light irradiation for the degradation of the Methyl orange dye in aqueous media. The antimicrobial activity of ZnO-Nps was checked by time kill method, presented the inhibition of growth against clinical isolates of Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) after 24 h. However, 12.5 and 6.25 µg is minimal inhibitory concentration (MIC) and 25 and 12.5 µg minimal bactericidal concentration (MBC) of ZnO-Nps against MRSA and E. coli respectively.