Here, we report synthesis and properties of a di-ruthenium acetylide molecular wire having a diethynylporphyrinatomanganese linker, and the effect of the coordination of electron-donor molecules to the Mn center on the metal-metal interaction is also described. Electrochemical and spectroscopic studies of the wire reveal highly charge delocalized properties. Addition of pyridine in the presence of [NBu4][PF6] causes electrochemical and spectroscopic changes, suggesting modulation of the rutheniumruthenium interaction. On the basis of a DFT study, the formation of a cationic bis-pyridine adduct has been confirmed to play a key role in the modulaion.