In most polar solvents, Nile red will not fluoresce; however, when in a lipid-rich environment, it can be intensely fluorescent, with varying colors from deep red (for polar membrane lipid) to strong yellow-gold emission (for neutral lipid in intracellular storages).

[2] Nile red has applications in cell biology, where it can be used as a membrane dye which can be readily visualized using an epifluorescence microscope with excitation and emission wavelengths usually shared with red fluorescent protein.

Nile red has also been used as part of a sensitive detection process for microplastics in bottled water.

[3][4] Additionally, nile red is a remarkable candidator in fabricating membrane for different sensors to detect environmental changes, such as taste, gas, pH, etc.

Alternatively, Nile red and its analogs (naphthooxazine dyes) can be prepared by acid-catalyzed condensation of corresponding 5-(dialkylamino)-2-nitrosophenols with 2-naphthol.