A new fluorescent dye, 4-ethoxycarbonylmethyl-2-methyl-7-hydroxyquinoline (TG) was obtained unexpectedly from the BiCl3-catalyzed Pechmann condensation. TG emits green fluorescence at 509 nm in water. For live-cell imaging applications, TG derivatives TG1-TG3 were prepared. Under physiological conditions, HEp-2 cells were immediately stained upon addition of a solution of TG3.