Silver nanoparticles (Ag NPs) were synthesized using Alternanthera sessilis leaf and Oregano root extract in an eco-friendly fashion and their significant physicochemical and optochemical properties were ascertained for nano-defined characteristics. The UV-visible spectrum showed a single and distinct absorbance peak at 433 nm (Alternanthera sessilis) and 425 nm (Oregano), typical SPR (surface plasmon resonance) for silver. Structural studies revealed nano-crystal with face centre cubic (FCC) symmetry with monodispersed nature. SEM studies showed spherical-shaped particles and the purity determined from EDX spectrum. The synthesized Ag NPs showed that antibacterial activity was studied. There was a significant inhibitory effect toward clinically important pathogens viz. B. subtilis, S. aureus, P. aeruginosa, and E. coli exposed to Ag NPs at different concentrations.