A new PVC membrane electrode that is highly selective to Cu(II) ions was prepared by using 3,6, 9,14-tetrathiabicyclo[9.2.1]tetradeca-11,13-diene as a suitable neutral carrier. The electrode exhibits a Nernstian slope of 28+/-1mV per decade at 25 o C for Cu 2 + ions over a wide concentration range (6.3x10 - 7 to 2.5x10 - 1 M). It has a response time of<10s and a detection limit of 3.2x10 - 7 M. The proposed electrode revealed good selectivities over a wide variety of other cations including alkali, alkaline earth and transition metal ions and could be used for at least 2 months without any divergence in potential. It was applied to the direct determination and potentiometric titration of copper ions.