Tris(3-chlorophenyl)phosphine is primarily used as a ligand in coordination chemistry, particularly in the synthesis of metal complexes. It plays a significant role in catalysis, especially in palladium-catalyzed cross-coupling reactions such as Suzuki and Heck reactions, which are essential in the production of pharmaceuticals and fine chemicals. Its electron-withdrawing chlorine substituents enhance the stability and reactivity of the resulting metal complexes, making it valuable in organic synthesis. Additionally, it finds application in materials science, where it is used to modify the properties of polymers and other advanced materials.