AbstractAn eco‐friendly gold‐based catalyst supported on proline decorated montmorillonite was synthesized. The catalyst was characterized by combination of Fourier‐transform infrared spectroscopy (FT‐IR), Field Emission Scanning Electron Microscopy (FE‐SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), Brunauer–Emmett Teller (BET) surface area analysis, Ultraviolet–visible spectroscopy (UV‐Vis), Energy‐dispersive X‐ray spectroscopy (EDX), thermo gravimetric analysis (TGA) and atomic absorption spectroscopy (AAS) techniques. The synthesized catalyst was found to be a highly efficient heterogeneous nanocatalyst for multi component A3 coupling reaction of aldehyde, amine and alkyne in water as a green solvent at room temperature. This novel catalyst promotes multicomponent reaction of a large library of functional substrates under mild and sustainable conditions (water as a green solvent at ambient temperature). In addition, the catalyst could be easily recovered by simple filtration and reused for at least 6 cycles without losing its activity.