Aqueous ammonia, ''paeonol'' (2-hydroxo-4-methoxy-acetophenone) and copper(II) salts readily form the neutral bis-iminatocopper(II) complex, a new compound. The solid contains the trans isomer, with four-coordinated copper(II). Bis-paeonolatocopper(II) itself exists as a dihydrate and as the anhydrate which is at least dimorphic.