We have developed a green and environmentally friendly approach for the synthesis of silver nanoparticles (Ag NPs) using Radix Puerariae plant extract via a novel chemical route. The prepared Ag NPs has been characterized by TEM, XRD, SEM, DLS, EDX, and UV–Vis. Further, catalytic application of this fascinating nanomaterial has been utilized in the synthesis of pyrimido[1,2-b]indazole derivatives via one-pot three component coupling reaction under solvent-free conditions.