Methyltetrazine-NHS ester is widely used in bioorthogonal chemistry for labeling and modifying biomolecules. Its primary application lies in the selective conjugation of biomolecules, such as proteins, peptides, and antibodies, through a fast and efficient reaction with strained alkenes or alkynes. This makes it a valuable tool in fluorescence imaging, where it enables the tagging of specific cellular components for visualization under a microscope. Additionally, it is employed in drug delivery systems to attach targeting moieties to therapeutic agents, enhancing their specificity and efficacy. The compound is also utilized in the development of diagnostic probes, where its rapid and selective reactivity allows for the detection of specific biomarkers in complex biological samples. Its stability and reactivity under physiological conditions make it a preferred choice for various biomedical research applications.