Trifluoroethylamine-substituted solvatochromic fluorophores exhibit polarity-insensitive high brightness.

In this study, we have uncovered that trifluoroethylamine-substituted solvatochromic fluorophores maintain consistently high and stable fluorescence intensity in diverse polar environments, including highly polar and protic solvents. The 1,8-naphthalimide derivatives serve as a buffering fluorogenic indicator for lipid droplet morphology during the fusion process and ratiometric probe for microenvironment polarity based on Halo-tag technology.