The S-4-symmetric copper(I) tetramer C(u)4(MEPA)(4), MEPAH = N-(2-mercaptoethyl)picolylamine, exhibits a tetragonal bisphenoidal (D-2d) arrangement of the metal centers. The MEPA(-) ligands use mu-thiolate and the amine nitrogen centers for coordination, while the 2-pyridyl groups are not involved in Cu(I) coordination but in an intramolecular hydrogen-bonding network with the metal-bound and thus cooperatively activated secondary amine functions.