N-(Phenylseleno)phthalimide is primarily utilized in organic synthesis as a versatile reagent. It is commonly employed in the selenylation of various organic compounds, facilitating the introduction of phenylseleno groups into molecules. This is particularly useful in the synthesis of selenides, which are valuable intermediates in the production of pharmaceuticals and agrochemicals. Additionally, it serves as a key component in the preparation of selenium-containing heterocycles, which have applications in medicinal chemistry and materials science. Its role in radical reactions also makes it a valuable tool for constructing complex molecular architectures in synthetic organic chemistry.