Plasmonic silver nanoparticles (AgNPs) doped ZnO (Ag-ZnO) nanoplates were synthesized by simple wet chemical method in presence of hexylamine with an intent to improve the visible light mediated photocatalytic activity of ZnO. Powder X-ray diffraction (PXRD) analysis confirmed the integration of AgNPs with ZnO nanoplates. High-resolution transmission electron microscopic (HR-TEM) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of ZnO nanoplates and AgNPs doping. The concentration of Ag in ZnO nanoplates was increased by increasing hexylamine concentration. Ag-ZnO hybrid nanoplates exhibited efficient degradation of organic dyes (methyl orange (MO), methylene blue (MB), Eosin Y (EY) and rhodamine B (RB)) in presence of sun light compared to the pristine ZnO. Further, AgNPs doping with ZnO strongly enhanced anti-biofilm activity and showed strong prevention of colonization. The increase of AgNPs concentration in ZnO nanoplates exhibited enhancement of both photocatalytic and anti-biofilm activity that might be attributed to the improved light absorption in the visible region.