Butylamine hydroiodide is primarily used in organic synthesis as a reagent for introducing iodine into various compounds. It is particularly effective in the preparation of iodinated organic molecules, which are valuable intermediates in pharmaceuticals and agrochemicals. Additionally, it serves as a catalyst or co-catalyst in certain chemical reactions, enhancing the efficiency of processes like alkylation or amination. Its application extends to the field of material science, where it is utilized in the synthesis of specialized polymers and coatings. In research, it is often employed for studying reaction mechanisms involving iodine or amine groups.