(Me)Tz-butanoic acid is a chemical reagent featuring a tetrazine moiety that reacts with molecules containing TCO groups through an inverse electron-demand Diels-Alder reaction (iEDDA). This reagent is utilized as a tetrazine linker that pairs with dienophilic molecules via a copper-free Click reaction (notably the Diels-Alder reaction). Additionally, (Me)Tz-butanoic acid serves as a potent click chemistry tool due to its componentry.