The title compound, C 16 H 16 Br 2 O 4 S 2 , which is a precursor for the synthesis of oligothiophenes and their substituted homo-logues, was synthesized and its X-ray crystal structure determined at 100 K. The experimental electron-density parameters for the available atom types were transferred from the ELMAM2 database. The compound lies about an inversion centre, which coincides with the mid-point of a C—C bond. The molecules in the crystal are linked by several types of weak interactions; the largest contact surfaces are for HÁ Á ÁH and HÁ Á ÁBr. Comment In the recent past, oligothiophenes and their substituted homologues have attracted the attention of the scientific community as they are a promising class of organic semiconductor materials for applications in the production of organic field-effect transistors and as electronic devices (Roncali, 1992). These-conjugated materials have found important applications, for example in organic solar cells (Ma et al.,