3-(Diphenylphosphino)propanoic acid (L2) has proved to be an efficient ligand for the copper-catalyzed C N coupling reactions. N-arylation of imidazoles with aryl iodides catalyzed by CuCl/L2 was smoothly carried out in DMSO at 100 °C with a yield up to 98%. N-arylation of 1H-pyrazole with aryl iodides and bromides catalyzed by Cu(OAc) 2 /L2 in 1,4-dioxane also gave the corresponding products with yields of 40%–98%. ... 3-(Diphenylphosphino)propanoic ...