An efficient and eco-friendly method has been developed for the synthesis of 1,4 disubstituted 1,2,3-triazoles using the eggshell-supported-Cu(I) metformin complex as a natural and heterogeneous catalyst. The catalyst prepared is characterized by FT-IR spectroscopy, SEM, and ICP techniques. Terminal alkynes were successfully reacted with alkyl chloride and sodium azide in the presence of CuI immobilized on eggshell in water at room temperature. This method offers many advantages such as short reaction times, low cost, use of a reusable catalyst, and simple purification procedures.Moreover, the catalyst could be recovered and recycled four times. Manuscript profile