Mn3O4 nanoparticles (NPs) find a broad range of applications in catalysts, energy storage devices, wastewater remediation, biosensors, photocatalysts, medical/antimicrobial agents, and in controlling drug-resistant pathogens. In the present work, Mn3O4 NPs were successfully produced by using a simple, cheap, and plant-mediated green synthetic route. The leaf extract of Coriandrum sativum was treated with MnNO3.6H2O at 60oC and pH 12 to produce Mn3O4 NPs. The synthesized NPs were characterized by XRD, FTIR SEM, and UV-Visible analyses. Their electrochemical properties were investigated by cyclic voltammetry (CV) and they were also subjected to antibacterial evaluation studies by the disc diffusion method. The XRD analysis revealed the tetragonal structures of Mn3O4 NPs with a crystallite size of 23.62 nm. FTIR spectroscopy displayed the Mn-O vibrations at 730 cm-1. SEM analysis verified the aggregated and flake-like morphology of Mn3O4 NPs. UV-Visible spectroscopy revealed the absorption peaks at 232 and 360 nm, which correspond to the permissible charge transfer transitions of O2-→Mn2+ and O2-→Mn3+, respectively. The CV curves clearly indicated the redox reactions and the reversible behavior of Mn3O4 NPs. The antibacterial activity of Mn3O4 NPs against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) was also evaluated using ciprofloxacin as a standard reference drug.