3-Amino-4-methoxybenzenesulfonic acid in solid state exists in the zwitterionic form, 3-ammonio-4-methoxybenzenesulfonate. 3-Amino-4-methoxybenzenesulfonic acid was incorporated via direct coprecipitation between the sheets of a layered double hydroxide (LDH) of intralamellar composition Cu2Cr(OH)6.