(3-Bromophenyl)diphenylphosphine oxide is an organophosphorus compound primarily used as a synthetic intermediate in the preparation of phosphine ligands and other phosphorus-based materials. The bromine group enables further derivatization through palladium-catalyzed cross-coupling reactions, facilitating the synthesis of substituted phosphines for catalysis. It is applied in the development of pharmaceuticals, agrochemicals, and advanced materials, including organic electronics and luminescent compounds. Additionally, it serves as a precursor for chiral phosphorus reagents in asymmetric synthesis and as an additive in polymer formulations to enhance stability and performance.