The strategy of chemical coprecipitation is implemented to synthesize nanoparticles of pristine CuSe, 5 and 10% Nidoped CuSe, and 5 and 10% Zn-doped CuSe. All of the nanoparticles are found to be near stoichiometric by the evaluation of X-ray energy using electron dispersion spectra, and the elemental mapping shows uniform distribution. By X-ray diffraction examination, all of the nanoparticles are identified as being single-phase and having a hexagonal lattice structure. Field emission microscopy with electrons in both scanning and transmission modes affirmed the spherical configuration of the nanoparticles. The crystalline nature of the nanoparticles is confirmed by the presence of spot patterns observed in the selected area electron diffraction patterns. The observed d value matches well with the d value of the CuSe hexagonal (102) plane. Findings from dynamic light scattering reveal the size distribution of nanoparticles. The nanoparticle's stability is investigated by ζ potential measurements. Pristine and Ni-doped CuSe nanoparticles exhibit ζ potential values in the preliminary stability band of ±10 to ±30 mV, while Zn-doped nanoparticles feature moderate stability levels of ±30 to ±40 mV. The potent antimicrobial effects of synthesized nanoparticles are studied against Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Enterobacter aerogenes, and Escherichia coli bacteria. The 2,2-diphenyl-1-picrylhydrazyl scavenging test is used to investigate the nanoparticle's antioxidant activities. The results showed the highest activity for control (Vitamin C) with an IC 50 value of 43.6 μg/mL, while the lowest for Nidoped CuSe nanoparticles with an IC 50 value of 106.2 μg/mL. Brine shrimps are utilized for in vivo cytotoxicity evaluation of the synthesized nanoparticles, which demonstrates that 10% Ni-and 10% Zn-doped CuSe nanoparticles are more damaging on brine shrimp instead on other nanoparticles with a 100% mortality rate. The lung cancer cell line of human (A549) is used to investigate in vitro cytotoxicity. The results indicate that pristine CuSe nanoparticles are more effective in the context of cytotoxicity against the A549 cell lines, possessing an IC 50 of 488 μg/mL. The particulars of the outcomes are explained in depth.