<p>This study investigates the incorporation of carbon quantum dots into polysaccharide-based polyurethane hydrogels using green methodologies employing deep eutectic solvents to obtain composites with improved properties for adsorbing and photodegrading dyes while maintaining sustainability. The mechanical properties, swelling behavior, hydrolytic degradation, stimuli-responsive properties, and the ability of carbon quantum dots, polyurethanes, and composites to adsorb and photodegrade an anionic and a cationic dye were evaluated. The findings demonstrate that the composites exhibit promising advantages for removing and degrading dyes commonly found in water bodies, achieving a degradation efficiency of Congo red above 90% using a composite dose of 3&#xa0;g L⁻¹, even at dye concentrations lower than 20&#xa0;mg L⁻¹. This research underscores the potential for sustainable synthesis of polysaccharide-based polyurethane/carbon quantum dots composite hydrogels, paving the way for developing high-performance, eco-friendly polymer materials for next-generation applications in environmental remediation and advanced engineering.</p> Graphical abstract <p></p>