Fig. 1. (a) UV and emission spectra of fluorescent aminomaleimides (2a–c) and alkoxybromomaleimides (3a–b); (b) fluorescence quantum yields of the singly substituted maleimides (2a–e, 3a–d) against excitation and emission wavelengths (recorded at 10 μM in diethyl ether); (c) aminomaleimides (2a–c) in 8 solvents (1–8: H₂O, MeOH, DMF, dioxane, THF, Et₂O, CH₂Cl₂ and cyclohexane) under UV light (365 nm).