The oxo-centered triruthenium-acetate cluster complexes with general formula [Ru3(μ3-O)(μ-OAc)6(L)2L′]n+ (L and L′ = axial ligand, n = 0, 1, 2) show attractive ligand substitution reactivity, multiple redox behavior and rich mixedvalence chemistry. The axial ligands L and L′ are comparatively labile and readily substitutable. Although the Ru3(μ3-O)(μ-OAc)6 cluster core possesses high stability, displacement of one of the bridging acetates has been achieved by using π-delocalized N-hetrocyclic ligands with low π∗ energy levels. Ligand substitution not only affords an excellent means of tuning the redox levels of electron transfer processes, but also provides a feasible approach to design ligand-linked triruthenium cluster oligomers with desired properties. This article reviews the recent progress in the ligand substitution chemistry of oxo-centered triruthenium–acetate complexes with parent Ru3(μ3-O)(μ-OAc)6 cores. The syntheses, redox and spectroscopic properties, and mixed valence chemistry of these oxo-centered triruthenium cluster derivatives are summarized to correlate structures with properties.