A novel fluorescent chemosensor calix[4]arene L, containing two fluorogenic coumarin units at the lower rim has been
synthesized via click reaction. The structure of this chemosensor, was characterized by IR, NMR spectra and elemental
analysis. Ion-binding properties of L were investigated in acetonitrile with different metal ions and the recognition process
was monitored by fluorescence, UV-Vis and 1H NMR spectral changes. In comparison with other metal ions, chemosensor
L showed a specific selectivity toward copper ions . The Job plot analysis revealed that the binding between L with Cu2+
is in 1:1 stoichiometry. The association constant (Ka) for the complex L.Cu2+ was found to be 1.6 × 105 M−1. The limit of
detection of the sensor L was determined to be 5.4 × 10−7 M. This sensitive and selective chemosensor was successfully
applied for the detection of Cu2+ ions in human blood serum with 90–100% recovery.