The novel bridging ligand 3,6-bis(phenylcyanamido)-1,2,4,5-tetrazine (tdpcH2) and its dinuclear complex [{Ru(ttpy)(bpy)}2(μ-tdpc)][PF6]2 were prepared and characterized by elemental analysis and 1H NMR spectroscopy. Cyclic voltammetry and vis-NIR and IR spectroelectrochemistry of [{Ru(ttpy)(bpy)}2(μ-tdpc)]2+ showed that [{Ru(ttpy)(bpy)}2(μ-tdpc)]3+ is a Class II mixed-valence system with metal−metal coupling of 400 cm−1 assuming a transition dipole moment length of 21 Å. DFT calculations of tdpc2− suggested that the stability of the HOMO results in weak metal−metal coupling via the hole-superexchange mechanism.