4-(4-Amino­phenyl­sulfon­yl)anilinium toluene-4-sulfonate

In the title p-toluene­sulfonate salt of the drug dapsone, C₁₂H₁₃N₂O₂S⁺·C₇H₇O₃S⁻, the dihedral angle between the two aromatic rings of the dapsone monocation is 70.19 (17)° and those between these rings and that of the p-toluene­sulfonate anion are 72.34 (17) and 46.43 (17)°. All amine and aminium H atoms are involved in inter­molecular N—H...O hydrogen-bonding associations with sulfonyl O-atom acceptors as well as one of the sulfone O atoms, giving a three-dimensional structure.