The fluorescence of the amphiphilic Dapxoyl® sulfonic acid is very environment sensitive and its fluorescence in water is very low, suggesting that this Dapoxyl® derivative may be useful as probes for conformational changes, denaturation, phosphorylation state and phase changes. Dapoxyl® dye exhibits a huge Stokes shifts (up to ~200 nm) and large extinction coefficient in some solvents.