This present application relates to fluorescent tetrazine-containing compounds consisting of a single pi-system. For example, a compound of Formula (I): or a salt thereof, wherein: F is a fluorophore, L is a conjugated linker, and Tz is a substituted or unsubstituted tetrazine； wherein the linker bridges the Tz and F moieties in a single conjugated pi-system. Also provided herein are methods of using the compounds provided herein for biomedical imaging.
