The reaction of 3-aminopyridine with formaldehyde afforded a clamplike ligand, 3,7-di(3-pyridyl)-1,5-dioxa-3,7-diazacyclooctane (L). The diffusion of a CH2Cl2 solution of L into an MeCN solution of CuX produced one decanuclear cluster [Cu10Cl10(L)4] (1) and two tetranuclear clusters [Cu4X4(L)2(MeCN)2] [X = Br (2), I (3)]. Compound 1 possesses a unique [Cu10Cl10] cluster core consisting of two stairlike [Cu5Cl5] fragments that share two μ6-Cl and two μ-Cl atoms. Compounds 2 and 3 have a stairlike [Cu4X4] cluster core that is anchored by two L ligands. The trans configuration of the two pyridyl groups of the free L ligand was converted into the cis configuration of the two pyridyl groups of each bridging L ligand in 1–3. The photoluminescence properties of 1–3 in the solid state were also investigated.