For practical applications, the same tests were examined in aqueous solution. Interestingly, Cu2þ triggered a color change from yellow to colorless and quenching in fluorescence in 10% aqueous acetonitrile solution (Fig. S1eS2), whereas Al3þ did not lead to a change in either absorption or fluorescence. These results indicate that 1 shows potential as a practical colorimetric and fluorescent chemosensor for Cu2þ with a high selectivity in aqueous solution