3-Bromothiophene is an organosulfur compound with the formula C4H3BrS. It is a colorless liquid. It is a precursor to the antibiotic timentin and the vasodilator cetiedil. 3-Bromothiophene is an organosulfur compound with the formula C4H3BrS. It is a colorless liquid. It is a precursor to the antibiotic timentin and the vasodilator cetiedil. Unlike 2-bromothiophene, the 3-bromo isomer cannot be prepared directly from thiophene. It can be prepared by debromination of 2,3,5-tribromothiophene, which is obtained by bromination of thiophene.