A wide range of diaryl selenides can be synthesized through CSe bond formation using readily available copper(I) iodide as catalyst under mild reaction conditions (82C) from aryl iodides and diphenyl diselenide. In this coupling reaction, solvent acetonitrile acts as ligand for copper(I) iodide and no external ligand is required. Less reactive aryl bromides also provide the di-aryl selenides in good isolated yields. © Georg Thieme Verlag Stuttgart • New York.