Pure and 5, 10 and 15 wt % Co-doped CuS (CuS:Co) nanoparticles were prepared by precipitation method. Diffraction peaks related to hexagonal structure was observed. Decreased crystallite size was realized as Co content increases. The inclusion of Co in the doped samples was confirmed by EDS spectra. Increased rate of radiative recombination increased the PL intensities of the doped samples. Co doping improved electrochemical, third order NLO, magnetic, and antimicrobial characteristics. The 10 wt percent co-doped CuS sample, which has superior electrochemical, magnetic, NLO, and antibacterial capabilities, was produced utilising cationic polysaccharide chitosan in a green manner. Chitosan untreated and loaded 10 wt% Co-doped CuS NPs have crystallite sizes of 61 and 55 nm, respectively. The interaction of CuS:Co NPs with chitosan biopolymer leads in improved electrochemical behaviour for the chitosan-loaded sample. The effective attraction between chitosan amino groups and the bacterial cell membrane results in enhanced antibacterial property for the chitosan loaded sample.