Used primarily in photochemotherapy, particularly for treating skin conditions like psoriasis, vitiligo, and eczema. It is applied topically or taken orally before exposure to UVA light, enhancing the skin's sensitivity to UV radiation and promoting repigmentation. Also employed in research for studying DNA interactions and repair mechanisms due to its ability to form photoadducts with DNA under UV light. Additionally, it has applications in the treatment of cutaneous T-cell lymphoma, where it aids in targeting malignant cells during photopheresis therapy.