Used in bioconjugation chemistry for site-specific protein labeling due to its rapid inverse electron-demand Diels-Alder (IEDDA) reaction with strained alkenes or alkynes. This enables efficient tagging of biomolecules in live cells without interfering with native biological processes. Commonly applied in imaging, targeted drug delivery, and development of antibody-drug conjugates where high selectivity and fast reaction kinetics are required. Also utilized in pretargeted imaging strategies in nuclear medicine, allowing for improved contrast and reduced background signal. Its stability in physiological conditions and fast ligation kinetics make it suitable for real-time tracking of cellular events.