Photophysical characterization and fluorescence cell imaging applications of 4- N -substituted benzothiadiazoles.

In this work, a series of fluorescent 2,1,3-benzothiadiazole derivatives with various N -substituents in the 4-position was synthesized and photophysically characterized in various solvents. Three compounds emerged as excellent fluorescent probes for imaging lipid droplets in cancer cells. A correlation between their high lipophilicity and lipid droplet specificity could be found, with log  P ≥ 4 being characteristic for lipid droplet accumulation.