Used primarily in research and specialized optical applications, this compound serves as a precursor for the synthesis of other thulium-containing materials. It finds application in the preparation of luminescent materials and phosphors, especially in devices requiring near-infrared emission. Due to its paramagnetic properties, it is also studied in magnetic susceptibility experiments and as a dopant in solid-state lasers. In analytical chemistry, it acts as a calibration standard for mass spectrometry and spectroscopy techniques. Its hydrate form is useful in solution-based processes where controlled release of thulium ions is required.