Reaction of Mo-2(dpa)(4) (dpa = 2,2'-dipyridylamido) with 1/2 equiv of [Ru(CO)(3)Cl-2](2) in molten naphthalene at 250 degrees C provides facile access to the first all-second-row transition metal heterometallic chain compound, MoMoRu(dpa)(4)Cl-2 (1). The one-electron oxidized compound [MoMoRu(dpa)(4)Cl-2] (OTf) (2) is synthesized by reaction of 1 with FeCp2(OTf). X-ray crystallography reveals a contraction of the Mo-Ru bond distance from 2.38 angstrom in 1 to 2.30 angstrom in 2, and an elongation of the Mo-Mo bond distance from 2.12 angstrom in 1 to 2.21 angstrom in 2. The short Mo-Ru bond distances indicate significant electron delocalization along the Mo-Mo-Ru chain, which is quantified by density functional theory (DFT) calculations. Molecular orbital analyses of both compounds based on DFT results reveal full delocalization of the orbitals of sigma and pi symmetry for both compounds. Additionally, delta orbital delocalization is observed in 2.