2-Diphenylphosphinobenzoic acid is an organophosphorus compound with the formula (C<sub>6</sub>H<sub>5</sub>)<sub>2</sub>PC<sub>6</sub>H<sub>4</sub>CO<sub>2</sub>H. It is a white solid that dissolves in polar organic solvents. The ligand is a component of catalysts used for the Shell higher olefin process. It is prepared by the reaction of sodium diphenylphosphide with the sodium salt of 2-chlorobenzoic acid.