A novel supramolecular model for the cupric type II site of proteins is described. The system is based on a calix[6]arene that is functionalized with three imidazole groups, providing a biomimetic coordination site in a hydrophobic conic cavity. The bisaquo, five-coordinate copper(II) complex is mononuclear and stable. The calixarene acts as a molecular funnel for nitriles, which can selectively substitute one of the aquo ligands. [GRAPHICS]