Abstract: Wurtzite‐type monodisperse CuInS2 (I) and CuInSe2 (II) nanoparticles are prepared by controlled solvothermal reaction of (Ph3 P)2 CuIn(XEt)4 (X: S, Se; prepared according to the literature) and S8 (no additional Se source for CuInSe2 ) in THF (autoclave, 140—200 °C, 24 h).