3,6-dimethyl-10-p-tolyl-9-oxa-10-phosphaanthracene), C(21)H(19)OP, is a precursor for the preparation of a bidentate xanthene-based ligand, in which the dihedral angle between the toluene ring and the phenoxaphosphine ring system is 83.26 (3)°. The geometry at the P atom is pyramidal, resulting in a longer C-P bond length as compared to the two ring C-P bonds.