The trinuclear complex ion [(NC)(OC)3Re(MoS4)Re(CO)3(CN)]2- 1(2-) is reversibly reduced to a Mo(V) containing trianion 1(3-), which exhibits hypsochromically shifted charge-transfer bands, bathochromically shifted CN, CO and MoS stretching frequencies and an axial EPR signal with g(parallel-to) > g(perpendicular-to).