We have extended these insights into the factors enabling or preventing metal-metal σbonding in dicobalt complexes to understand the nature of metal-metal bonding in two related dicobalt compounds with silane and hydride ligands. We show that ligand field strength can alter the relative stability of Co 3d orbitals, thus changing the occupancy of the orbitals with appropriate symmetry for σ-overlap. This either allows or prohibits Co-Co σ-bond formation.