Pyrene hydrazide is a carbonyl reactive dye for the attachment of pyrene polycyclic aromatic hydrocarbon residues to aldehydes and ketones.
Pyrene is a blue-emitting fluorescent label which is especially useful as a proximity probe. When two pyrene residues are located close to each other, a longer-wavelength excimer fluorescence can be detected. Pyrene can also be FRET donor to other fluorophores. Its excited state possesses an unusually long lifetime of more than 100 ns, which allows to use this fluorophore in time-gated experiments.