Bioactive compound functionalized plasmonic systems are evolving as a promising branch of nanotechnology. In this communication the synthesis of bioactive compound mimosine-based silver nanoparticles (AgNPs) and their non-linear optical and thermo-optic properties are presented. UV-Visible spectroscopy, optical bandgap measurement, fluorescence spectroscopy, and high-resolution transmission electron microscopy (HRTEM) techniques were used to characterize the synthesized AgNPs. An open aperture z-scan technique was used to determine the non-linear optical parameters. A very strong reverse saturable absorption (RSA) and low optical limiting threshold were observed for the present mimosine decorated AgNP system. The thermo-optic property of the present system was evaluated using a highly sensitive dual beam mode matched thermal lensing spectroscopic technique. A comparison of the low limiting threshold (242 MW cm−2) and thermo-optic property (thermal diffusivity, D = 1.13 × 10−7 m2 s−1) with similar systems proves its capability for non-linear optical and thermo-optic applications. We report the synthesis and non-linear optical properties of highly stable mimosine-decorated silver nano particles (AgNPs). The as-synthesized AgNPs were characterized by UV-visible absorption, fluorescence spectroscopy, and high resolution transmission electron microscopy. Low optical limiting threshold and promising value of thermal diffusivity point to the application potential of the system. [ABSTRACT FROM AUTHOR]