Used as a source of thulium ions in research and development of luminescent materials, particularly in the synthesis of phosphors for specialized lighting and display technologies. Employed in the preparation of catalysts for organic transformations where rare earth metals enhance reaction efficiency. Serves as a dopant in solid-state devices and lasers operating in the near-infrared range, benefiting medical and telecommunications applications. Utilized in scientific studies involving paramagnetic properties due to its unique electron configuration, making it suitable for magnetic resonance and cryogenic experiments. Also applied in the calibration of radiation detection equipment because of its stable isotopic forms and predictable emission characteristics.