Amberlite resin formate (ARF) with a polyionic polar environment is successfully utilized as a unique support for immobilization of stabilized Cu2O nanoparticles (NPs). The composite [Cu2O@ARF] is characterized by FT-IR, XRD, XPS, HR-TEM, and ICP-AES analyses. The HR-TEM results confirm existence of fairly dispersed Cu2O NPs with average diameter (similar to 5-7 nm) onto the resin surface, while ICP-AES analyses show loading of copper (10.8 mg) per gram of the resin composite (1.08 wt % of Cu). The ionic resin with counteranions (HCOO-) could reduce precursor Cu(II) to Cu(I) and stabilize Cu2O NPs. The as-synthesized composite acts as a robust, efficient, and recyclable catalyst for efficient construction of a 1,2,3-triazole ring under aqueous and aerobic conditions. The TOF (219 h(-1)) is found significantly high as compared to that of some related existing catalysts (120 h(-1)). The prowess of the catalyst is further demonstrated in the synthesis of a triazole-bearing antitumor drug molecule.