1,4-Dibromo-2,5-diiodobenzene is a useful synthetic intermediate in the synthesis of Benzo[1,2-b:4,5-b']dithiophene; a reagent in the synthesis of high-crystalline medium-band-gap polymers used for organic photovoltaic cells. Benzo[1,2-b:4,5-b']dithiophene is also a precursor in the preparation of benzodithiophene derivatives which are useful as hole injection material, hole transport material, or fluorescent material in organic electroluminescence devices.