Binuclear metal-hydroxide centers are implicated in many protein hydrolases. Here, we show that the binucleating ligand N,N,N’,N’-tetrakis(2-pyridylmethyl)-1,3-diamino-2-propanol (L-OH) reacts with 2 equiv of Cu-I and O-2, giving the tetranuclear complex [Cu-4(L-O-)(2)(mu-OH-)(2)](4+) (1) (X-ray), established to give binuclear species 2 upon dissolution in CH3CN. Labeling experiments show that the hydroxide moiety in 2 acts as a nucleophile for the efficient hydrolysis of unactivated acetate esters, yielding the mu-acetato-bridged complexes 3. Species 2 also slowly hydrates acetonitrile, yielding the mu-amidate-dicopper(II) complex 4.