Sulfur dyes, a type of dye produced in large quantities is known for its depth of color. But huge quantities of sulfides, electrolytes, and inorganic salts present in effluents containing sulfur dyes cause serious problems to environment, human, and aquatic life. Hence, in this research, chitosan – sodium tripolyphosphate@TiO2 [chitosan – TPP@TiO2] polymeric core/shell nanoparticles were synthesized by Ionic Gelation Method and their decolorization of sulfur black dye was examined. Structural confirmation was established through XRD and HR-TEM measurements. Surface morphological studies with elemental analysis were investigated using HR-SEM and EDS. Core/shell formation was confirmed through XPS measurements and their optical and thermal properties were explored. Sulfur black dye decolorization studies showed 88.3% decolorization within 6 min under dark conditions at ambient conditions due to the combined effects of adsorption and catalytic wet air oxidation (CWAO). The anti-bacterial and anti-fungal activities of chitosan – TPP@TiO2 core/shell nanoparticles were analyzed.