1-Bromo-3,4-dichlorobenzene-D2 is an intermediate used in the synthesis of Lamotrigine-13C3,d3, Major (L173253), which is an isotopically labelled Lamotrigine (L173250), an anticonvulsant and inhibits glutamate release, possible through inhibition of Sodium, Potassium and Calcium currents, and used in treatment of bipolar depression.