In this multifaceted experimental study, Schiff base (SL) stabilized nickel nanoparticles (SL-NiNPs) were synthesized and comprehensively characterized for their diverse applications. The synthesis process involved the formation of these nanoparticles through the reduction of ethanolic nickel chloride with sodium borohydride (NaBH4) under nitrogen gas, followed by their stabilization in toluene using tetraoctylammonium bromide (TOAB) as phase transfer agent and SL as capping agent. Characterization studies confirmed the successful synthesis and stabilization of SL-NiNPs, with UV-Vis spectral analysis, SEM, and TEM revealing their distinctive properties, including a spherical shape and a size of approximately 50 nm. The catalytic properties of SL-NiNPs was demonstrated in several reactions, including the reduction of 4-nitrophenol to 4-aminophenol, the degradation of methylene blue, and the reduction of methyl orange. These catalytic reactions showcased the efficiency and versatility of SL-NiNPs as effective catalysts for environmental and chemical processes. Furthermore, SL-NiNPs were employed in the coloration of cotton, leading to surface modification with nano-sized particles. SEM imaging illustrated the successful modification of cotton, enhancing its surface properties. The antimicrobial potential of SL-NiNPs-embedded cotton was assessed against various bacterial strains, revealing a dose-dependent inhibitory effect. As the concentration of SL-NiNPs increased, the diameter of the inhibition zones also increased, further emphasizing the potent antibacterial properties of these materials.