The development of multifunctional photocatalysts that efficiently operate under visible light remains a fundamental challenge for sustainable wastewater treatment and oxygen evolution. In this work, we report a novel reticular and high-entropy TiO₂-based nanotubular hybrid system integrated with Cu:ZnO nanoparticles and carbon quantum dots (C-dots), designed to achieve synergistic enhancement in charge dynamics and surface reactivity. The high-entropy configuration introduces lattice distortion and defect sites that extend the optical absorption edge and promote rapid charge separation, while the Cu:ZnO interface accelerates electron transport and facilitates multi-pathway redox reactions. Simultaneously, the C-dots serve as photonic antennas, enabling visible-light sensitization through π–π conjugation and energy up-conversion. Structural and optical analyses confirm the formation of a reticular nanotubular network providing hierarchical porosity and large interfacial area for catalytic interactions. Under simulated solar irradiation, the hybrid demonstrates remarkable photocatalytic efficiency, achieving over 95% degradation of organic contaminants and enhanced oxygen evolution activity compared to pristine TiO₂. The introduced design concept coupling reticular high-entropy stabilization with optoelectronic co-catalyst modulation presents a new paradigm for next-generation photocatalysts capable of simultaneous environmental remediation and clean energy generation.