Dissymmetrization of Benzothiadiazole by Direct C–H Arylation: A Way to Symmetrical and Unsymmetrical Elongated π‐Conjugated Molecules

5‐(7‐Bromo‐2,1,3‐benzothiadiazol‐4‐yl)‐2‐thiophenecarbaldehyde is a small building block of great interest for its use in the elaboration of symmetrical or unsymmetrical donor–acceptor π‐conjugated molecules for optoelectronic applications. Herein, a convenient, one‐pot, two‐component synthesis of this intermediate is reported, based upon a palladium‐catalysed, phosphine‐ and additive‐free, direct C–H arylation process. The synthesis has been studied in depth to obtain optimum yields and selectivity by an efficient and environmentally friendly strategy for sustainable synthesis.