The photoredox ability of a hexarhenium(III) cluster, (n-Bu4N)(4) (4+)[Re-6
(mu(3)-S)(8)Cl-6](4-), was examined in acetonitrile on the basis of emissio
n quenching experiments of the cluster by several neutral electron accepter
s. The quenching rate constants and the relevant activation parameters indi
cated that the hexarhenium(III) cluster acted as a useful photoredox sensit
izer towards various electron accepters.