The reaction of the organometallic carboxylic acid HOOCCCHCo2(CO)(6) with copper(II) methoxide leads to a new inorganometallic cluster; Cu-3{mu(2)-(CCHCo2(CO)(6))}(3). This cluster has a triangular core of copper(I) centers surrounded by three CCHCo2(CO)(6) fragments. The structure of the cluster has short Cu-Cu and Cu-Co distances (average 2.500 and 2.540 Angstrom, respectively). DFT calculations provide a rationalization of the peculiar bonding in this cluster.