A novel pi-conjugated Ru(II) dinuclear complex containing a new azobenzene-bridged bis(terpyridine) ligand was synthesized and its photochemical and electrochemical properties were investigated. The ligand underwent reversible trans-cis photoisomerization, whereas the Ru complex did not show such photoisomerization behavior. Cyclic voltammetry of the complex displayed a reversible one-step 2e(-) oxidation wave due to Ru(III)Ru(III)/Ru(II)Ru(II) and four le(-) reduction waves indicating the formation of mixed-valence states when the electrons are accumulated at the ligand-based orbitals.