O,N,N'-Triisopropylisourea is primarily used in organic synthesis as a reagent for the preparation of isocyanates and carbamates. It is particularly effective in facilitating the conversion of carboxylic acids to their corresponding isocyanates, which are valuable intermediates in the production of polymers, pharmaceuticals, and agrochemicals. Additionally, it serves as a condensing agent in peptide synthesis, aiding in the formation of peptide bonds. Its role in these processes is crucial for achieving high yields and selectivity, making it a valuable tool in both academic research and industrial applications.