An efficient silica-based inorganic-organic hybrid was synthesized by using 3-(2-aminoethylamino)propyltrimethoxylsilane as linker and 2-Quinolinecarboxaldehyde for Schiff's base formation which was further coordinated by Cu (II) chloride. The hybrid was characterized by relevant techniques, i.e., FT-IR, DRUV-Vis, SEM, EDX, ICP-AES, TGA and EPR technique which support its formation. The synthesized hybrid material was successfully used as heterogeneous catalyst for degrading Reactive Black-5 (RB-5), a non-biodegradable diazo dye. The degradation mechanism follows advanced oxidation technique utilizing hydrogen peroxide as an environmentally amiable green oxidant; where the hybrid catalyst decomposes H2O2 to generate ·OH free radicals. Effects of dye concentration, H2O2 concentration and temperature variation on dye degradation process were studied and best reaction conditions for maximum degradation of RB-5 were also worked out. The catalyst showed 87% dye degradation in 130 min at best reaction conditions. Easy separation, reusability and efficient dye degradation ability of the catalyst are the motivating factors for the development of such hybrid material for solving critical environmental issues.