Process for the preparation of a benzohetero-[1,3]diazole compound disubstituted with brominated heteroaryl groups which comprises reacting at least one dihalogenated benzohetero[1,3]diazole compound with at least one brominated heteroaryl compound. Said benzohetero[1,3]diazole compound disubstituted with brominated heteroaryl groups can be advantageously used in the synthesis of compounds useful in the construction of solar concentrators (LSCs—“Luminescent Solar Concentrators”). Furthermore, said benzohetero[1,3]diazole compound disubstituted with brominated heteroaryl groups can be advantageously used in the synthesis of photoactive polymers useful in the construction of photovoltaic devices (or solar devices) such as, for example, photovoltaic cells (or solar cells), photovoltaic modules (or solar modules), on both rigid or flexible supports. Furthermore, said benzohetero[1,3]diazole compound disubstituted with brominated heteroaryl groups can be advantageously used as precursor of monomeric units in the synthesis of semiconductor polymers.