Tetrabutylammonium triiodide is widely used in organic synthesis as a reagent for iodination reactions. It is particularly effective in the selective iodination of aromatic compounds, where it provides a controlled and efficient method for introducing iodine atoms into organic molecules. This is valuable in the production of pharmaceuticals, agrochemicals, and other fine chemicals where specific iodinated intermediates are required.

In addition, it serves as a source of iodine in electrochemical applications, such as in the preparation of iodine-based electrolytes for dye-sensitized solar cells. Its ability to release iodine ions makes it useful in these energy conversion devices, enhancing their performance and stability.

Furthermore, it is employed in analytical chemistry as a titrant for the determination of reducing agents. Its strong oxidizing properties allow for precise measurements in redox titrations, making it a reliable choice for quantitative analysis in various chemical processes.