A novel selective colorimetric chemosensor ANBP ((E)-(2-(((8-hydroxy-2,3,6,7-tetrahydro-1H,5Hpyrido[3,2,1-ij]quinolin-9-yl)methylene)amino)-5-nitrophenyl)(phenyl)methanone), based on the combination of benzophenone group and julolidine chromophore, was synthesized. Sensor ANBP showed rapid colorimetric responses toward Cu²⁺ (pale orange to pink) and F^- (orange to blue). The detection limit by ANBP to Cu²⁺(6.82 µM) was far below WHO guideline value (31.3 µM). Moreover, ANBP could quantify Cu²⁺ in aqueoussamples. 1:1 binding mode between ANBP and Cu²⁺ or F^- was proposed by ESI-mass analyses and Job plots. The remarkable color changes with Cu²⁺ and F ^- resulted from the intramolecular charge transfer (ICT) effect, which was demonstrated by theoretical calculations.

A highly selective colorimetric chemodosimeter ASAD, (E)-2-((4-(diethylamino)-2-hydroxybenzylidene) amino)-5-methoxybenzenesulfonic acid, was readily synthesized and characterized. The probe ASAD could selectively recognize hypochlorite (ClO^-) through an oxidative cleavage of C=N bond with acolor change from yellow to colorless and detected it down to a low concentration of 0.95 μM. Importantly, ASAD could be employed as a practical and efficient optical sensor for ClO− in test strips and water samples. Moreover, the detection process of ASAD to hypochlorite was demonstrated by UV-vis spectroscopy, NMR titration and theoretical calculations.