Used primarily as a reference standard in pharmaceutical quality control and analytical testing during the manufacturing and purification of ibrutinib, an anticancer drug. It helps in identifying and quantifying impurities in final drug products to ensure safety and compliance with regulatory standards. Also utilized in research settings to study degradation pathways and stability of ibrutinib under various conditions. Its structural similarity to the active pharmaceutical ingredient makes it critical for method validation in HPLC and mass spectrometry techniques.