Synergistic catalytic effects aid the photocatalytic reduction of CO
2 to CO by a dinuclear cobalt cryptate complex in CH
3CN/H
2O solution. In their Communication on
page 738 ff., D. C. Zhong, T. B. Lu, and co-workers demonstrate that one Co
II unit serves as a catalytic center and the other Co
II unit acts as an assistant catalytic site to facilitate the cleavage of the C−O bond of the O=C−OH intermediate, thus leading to a higher catalytic activity than for the corresponding mononuclear Co
II complex.