Used primarily as a photoinitiator in UV-curable systems, enabling rapid polymerization upon exposure to ultraviolet light. Commonly found in inks, coatings, and adhesives where fast curing and strong adhesion are required. Especially effective in printing inks for packaging due to its ability to initiate curing in pigmented formulations. Also utilized in overprint varnishes and industrial coatings where high efficiency and low yellowing are important. Its thioxanthone structure provides good absorption in the UV-A range, making it suitable for use with medium-pressure mercury lamps. Often combined with co-initiators like amines to enhance reactivity and reduce oxygen inhibition during curing.