Iron(III) bromide is primarily used as a catalyst in various organic synthesis reactions, particularly in the bromination of aromatic compounds. It facilitates the introduction of bromine atoms into organic molecules, which is essential in the production of pharmaceuticals, agrochemicals, and specialty chemicals. Additionally, it serves as a Lewis acid in chemical reactions, aiding in the formation of complex organic structures. In some cases, it is also employed in the synthesis of coordination compounds and in research applications for studying reaction mechanisms involving bromine.