A review is given, from an organometallic perspective, of the current state of knowledge of the structure and activity of the bimetallic Pt-Re-Al 2 O 3 catalysts used in petroleum reforming and of the known heteronuclear Pt-Re cluster complexes. Some comparisons between proposed structures, bonding and reactivity in the Pt-Re clusters present in the heterogeneous catalytic materials and in the well-defined clusters are made.