Nanoporous copper catalysts with tunable nanoporosity were fabricated from Cu₃₀Mn₇₀ alloy by controlling the dealloying temperature under free corrosion conditions. The tunable nanoporosity of CuNPore led to a significant enhancement of catalytic activity in click chemistry without using any supports and bases. Characterization of CuNPore surface, high reusability, leaching experiment, and formation of nanostructured copper acetylide revealed that the click reaction occurred at the catalyst surface and the Cu(I) species was the real catalytic active sites. The CuNPore catalyst system was also applied to the three-component coupling of terminal alkynes, tosyl azide and dialkylamines to afford the corresponding aminoimines in high yields.