Electrosorption is a developing water treatment method and operates by applying an electrical potential between two porous electrodes. In membrane based electrosorption system, ion-exchange membranes are placed in front of each electrode to prevent the passage of co-ions, resulting in enhanced salt removal and charge efficiencies. However, currently not many electrosorption systems exist which can selectively remove specific ions. Membrane based selective electrosorption systems that could selectively remove target ions can be useful for various water treatment applications. For example, produced water treatment requires selective removal of scale forming ions (Ba2+, Ca2+, Sr2+, SO42-) to prevent scale deposition in various piping and equipment surfaces. Furthermore, if using an electrosorption approach, ion selective approach would be more energy efficient. In this work, in the first stage, ion exchange polymer coated electrodes were developed, and a high salt removal and energy efficiency performance was obtained. In the second stage, a novel sulfonated polymer (PEDOT:PSS) coated electrode for selective electrosorption was developed. Ion selective electrosorption tests were conducted using a mixed salt solution consisting of CaCl2 and NaCl. Furthermore, applied voltage, feed flow rate and composition were varied to analyze their effect on the selectivity performance. The test results indicate that with this novel electrosorption system a highest Ca2+/Na+ selectivity of 8.21 ± 2.88 at 0.6 V could be achieved.