efficient catalyst is of great importance in pyrazolederivativessynthesis. Herein, rhombic dodecahedra Cu2O microcrystals were successfully synthesized, and employed as catalysts in the direct synthesis of alkenyl pyrazoles. The catalytic activity of the obtained Cu2O catalyst toward the synthesis of alkenyl pyrazoles via the reaction of p‐chlorophenyl hydrazone and 2,4‐pentanedione was studied. The results