Reaction Of Mo-2(pyphos)(4) (1) (pyphos = 6-diphenylphosphino-2-pyridonate) with Pd(dba)(2) (dba = dibenzylidene-acetone) afforded the Pd(0) complex Mo2Pd2(PYPhos)(4) (2) which has two Pd(0) centers at both axial positions of the Mo-2 core. The unsaturated Pd(0) centers of 2 were coordinated with donor molecules such as olefins, acetylenes, isonitriles, carbon monoxide, and triphenylphosphine to give the corresponding adducts, Mo2Pd2(pyphos)(4)(L)(2) (3a: L = acrylonitrile, 3b: L = fumaronitrile, 3c: L = tetracyanoethylene, 3d: L = diisopropyl fumarate, 3e: L = diethyl fumarate, 3f: L = dimethyl fumarate, 3g: L = dimethyl maleate, 3h: L = 2,6-xylylisocyanide, 3i: L = tert-butylisocyanide, 3j: L = dimethyl acetylenedicarboxylate, 3k: L = 1,4-benzoquinone, 31: L = 1,4-naphthoquinone, 3m: L = carbon monooxide, and 3n: L = triphenylphosphine). Oxidative 1,4-addition of ArSSAr and benzoyl peroxide to the Pd(0) centers of 2 afforded the corresponding Pd(I) complexes Mo2Pd2(SAr)(2)(pyphos)(4) (7a: Ar = C6H5, 7b: Ar = 4-Me3CC6H4, 7c: Ar = 4-MeC6H4, 7d: 4-NO2C6H4) and Mo2Pd2(OCOPh)(2)(pyphOS)(4) (9). Chemical oxidation of 2 with [CP2Fe][BF4] in CH3CN afforded a dicationic Pd(I) complex [Mo2Pd2(pyphos)(4)(CH3CN)(2)][BF4](2) (10a). Similarly, the reaction of 2 with [CP2Fe][BF4] in the presence of excess amounts of various donor molecules in THF gave rise to corresponding dicationic Pd(I) complexes [Mo2Pd2(pyphos)(4)(L')(2)][BF4](2) (10b; L' = dimethylsulfoxide, 10c: L' = THF, 10d: L' = benzonitrile, 10e: L' = p-methoxyphenylnitrile, 10f: L' = p-trifluoromethylphenylnitrile, 10g: L' = pyridine, and 10h: L' = p-dimethylaminopyridine), whereas complexes [Mo2Pd2(pyphos)(4)(CNXyl)(2)][BF4](2) (10i) and [Mo2Pd2(pyphos)(4)((CNBF4)-B-t](2)[BF4](2)(10i) were prepared by oxidation of the corresponding isonitrile-Pd(0) complexes 3h and 3i. Cyclic voltammetry of 10a-j displayed two different oxidation profiles of Pd(0) depending on the donor molecules: complexes 10a-f showed two waves ascribed to electron communication through monocationic species as intermediates, whereas complexes 10g-j showed one wave due to two-electron process. Furthermore, the oxidative addition of alkyl and aryl halides to 2 gave rise to two different reaction patterns: excess amounts of benzyl halides BnX (X = Cl, Br, I), PhCl, and PhBr, and 2 equiv of Phl reacted with 2 to give Pd(I) complexes Mo2Pd2(X)(2)(pyphos)(4) (4a: X = Cl, 4b: X = Br, 4c: X = 1), and the reactions of 2 with excess amounts of Phl and Mel afforded Pd(II) complexes Mo2Pd2(Ph)(2)vertical bar(2)(pyphos)(4) (11) and Mo2Pd2(CH3)(2)vertical bar(2)(Pyphos)(4) (13) bearing two "Pd(Ph)l" and "Pd(CH3)l" moieties.