2-Pyridyldiphenylphosphine, also known as Diphenyl-2-pyridylphosphine, is a tertiary phosphine ligand featuring a phosphorus atom bonded to two phenyl groups and one 2-pyridyl group. This hybrid structure combines both soft (phosphorus) and hard (nitrogen) donor atoms, making it a versatile chelating ligand in coordination chemistry and homogeneous catalysis. Its ability to bridge metal centers or coordinate through both phosphorus and nitrogen allows it to stabilize a range of metal complexes, particularly in catalytic systems such as hydrogenation, hydroformylation, and cross-coupling reactions. The electron-donating properties and steric bulk of the phenyl groups, combined with the coordination flexibility of the pyridyl ring, contribute to its popularity in organometallic and inorganic chemistry.