Novel bimetallic ruthenium platinum nano particles were synthesized using the Diospyros kaki plant leaf extract and then immobilized on the carbon substrates to make supported nanocatalysts. Various characterization techniques, such as XPS, TEM, and XRD showed the effective introduction of ruthenium platinum nanoparticles into the carbon supports. The biogenic Ru0.5Pt0.5/Vulcan XC catalyst displayed outstanding catalytic performance in selective hydrogenation of ortho-chloronitrobenzene under mild condition without adding solvent. The effects of catalyst parameters and reaction operating conditions on the catalytic activity were systematically studied and optimized. Moreover, the bimetallic catalyst showed superior stability and the catalytic performance was comparable to that of conventional reported catalysts.