The synthesis and characterization of a polycarbonate of p-tert-butylcalix[4]arene 4 are reported. It was synthesized by condensation of p-tert-butylcalix[4]arenetetraol derivative 3 with ethyl chloroformate. This new polymer possesses a hydrolyzable backbone and tunable hydrophobic/hydrophilic properties. The experimental results indicate that the polycarbonate was successfully synthesized with average molecular weight (M) over bar (w), (2.328 x 10(4) g/mol), which was determined by static light scattering method using a Berry plot. The structure of this polymer was determined by IR spectroscopy. The thermal properties were investigated using differential scanning calorimetry (DSC). The degree of crystallinity was measured by means of XRD. The extraction ability of compounds 3 and 4 toward alkali metal cations was studied using conductometry. It was observed that compound 4 had the highest extractability and selectivity toward Na+.