An unprecedented method for the palladium (II)-catalyzed direct halogenation of benzothiadiazole derivatives is reported here, which would allow the rational tuning of their electronic properties by further transformations. The key strategy is the combination of the double functions of benzothiadiazole as both an important moiety of functional materials and modifiable directing group. Various mono/polychlorinated, brominated, or iodinated benzothiadiazole products could be prepared efficiently, which can be converted into a wide range of valuable polyaromatic compounds with potential applications in material chemistry.