1-Phenylisoquinoline is primarily utilized in organic synthesis and pharmaceutical research. It serves as a key intermediate in the development of various biologically active compounds, particularly in the synthesis of alkaloids and other nitrogen-containing heterocycles. Its structural framework is valuable in designing molecules with potential therapeutic properties, such as anticancer, antimicrobial, and anti-inflammatory agents. Additionally, it is employed in the study of photophysical properties due to its aromatic system, making it useful in materials science for developing organic light-emitting diodes (OLEDs) and other optoelectronic devices. Its role in coordination chemistry is also notable, as it can act as a ligand for metal complexes in catalytic processes.