Through a combination of X-ray spectroscopy and supporting calculations, we obtain a detailed understanding of bonding and electronic structure in a series of dicobalt complexes supported by PNNP expanded pincer ligands. The dicobalt species in a pseudo-octahedral coordination environment supported by diethylsilane and hydride ligands show clear evidence of a bonding orbital with direct Co-Co σ-bonding and multicenter character, which has been characterized from both the occupied and vacant perspectives. The Co-Co σ-bonding results from symmetry-allowed overlap of the singly occupied Co 3𝑑 𝑥 2 -𝑦 2 orbitals, and leads to the formation of an electron pair in an energetically stabilized bonding MO. In these complexes, the hydride ligands have a significant impact on electronic structure, resulting from strong overlap with the vacant Co 3𝑑 𝑧 2 orbital. In contrast the dicobalt complexes in a tetrahedral coordination environment do not exhibit Co-Co σ-bonding, even when both Co centers are bound in the PNNP pocket. This lack of bonding is explained by the Co 3d orbitals with e symmetry in a tetrahedral ligand field, which have the appropriate orientation for σ-bonding, but are fully occupied for high-spin Co 2+ (d 7 ) ions.