N-(2-hydroxyethyl)-Naphthalimide is an N-substituted 1,8-naphthalimide used as a fluorescent probe and as a precursor for protection of amine groups. It is used to detect nucleic acids and their precursors, which quench the fluorescence of N-(2-hydroxyethyl)-naphthalimide. Nucleic acids quench the fluorescence most strongly followed by nucleosides and nucleobases, of which purine bases quench more strongly than pyrimidine bases. N-(2-hydroxyethyl)-Naphthalimide is electroactive and forms adducts with 1,3-dihydroxy benzene and 1,3,5-trihydroxybenzene. N-(2-hydroxyethyl)-Naphthalimide displays excitation spectra of 330-333 and 344-347 nm with emission spectra of 366-378 nm in solvents of varying polarities, with a higher Stokes shift in less polar solvents.