The novel rhodamine derivative (RATU) was synthesized by two-step reactions between rhodamine B (RB), tris(2-aminoethyl)amine (TAEA) and phenyl isothiocyanate (PITC) (Scheme 1). RB reacted with TAEA to get the intermediate (RTAA) following the references [24]. Then to a stirring CH3CN (10 mL) solution of RTAA (0.2 g, 0.35 mmol), PITC (167 μL, 1.4 mmol) was added dropwise and reacted at room temperature for 6 h. Next the solvent was removed under reduced pressure. The residue was separated by sillica-gel column chromatography with ethyl acetate/petroleum ether (1/2, v/v) as an eluent to afford a white solid RATU (49.7 mg). Yield, 57%. m.p. 141.7 °C.