Methyltetrazine-acid is widely used in bioorthogonal chemistry due to its rapid and selective reactivity with trans-cyclooctenes (TCOs) in click chemistry reactions. This property makes it a valuable tool for labeling and imaging biomolecules in live cells and tissues without interfering with native biological processes. It is also employed in the development of targeted drug delivery systems, where it enables the precise attachment of therapeutic agents to specific biomolecules. Additionally, its application extends to materials science, where it is used for surface functionalization and the creation of advanced polymeric materials.