Methyltetrazine-propylamine is widely used in bioorthogonal chemistry due to its rapid and selective reactivity with trans-cyclooctenes (TCOs) in the inverse electron demand Diels-Alder (IEDDA) reaction. This property makes it valuable for labeling and imaging biomolecules in live cells and tissues without interfering with native biological processes. It is particularly useful in click chemistry applications for attaching fluorescent dyes, drugs, or other functional groups to proteins, antibodies, or nucleic acids. Additionally, it plays a significant role in pretargeted imaging and drug delivery strategies, where it enables precise targeting and visualization of specific cellular components or diseased tissues. Its stability and efficiency in physiological conditions further enhance its utility in advanced biomedical research and diagnostics.