A new heterometallic Ni-II-Cu-II decanuclear cluster, {[Ni4Cu6(mu-OH2)(2)(dpkO(2))(8)(OAc)(4)-(H2O)(4)]center dot 2CH(3)OH center dot 17H(2)O} (1), has been synthesized by self-assembly of the constituent metal ions and the precursor di-2-pyridylketone (dpk) of multinucleating ligand dpkO(2)(2-) and is structurally characterized. The cluster 1 is formed by the union of two symmetry-related distorted cubane-like pentanuclear cores. A magnetic study of 1 reveals strong antiferromagnetic interactions operating through the Ni-O-Ni pathway, which is independent of the assumption D = 0 or D not equal 0. The pentanuclear cores are ferromagnetically coupled, as supported by density functional theory calculations.