A copper(II) ion-selective PVC membrane sensor based on 2-(1'-(4'-(1''-hydroxy-2''-naphthyl)methyleneamino)butyl iminomethyl)-1-naphthol (BHNB) as a novel Schiff base containing a sensing material has been successfully developed. The sensor exhibits a good linear response of 29 mV per decade within the concentration range of 10(-1)-10(-6) M of Cu2+. The sensor shows good selectivity for copper(II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. The BHNB-based sensor is suitable for use with aqueous solutions of pH 3.5-7.0 and displays minimal interference by Sr(II), Cd(II), Hg(II), Zn(II) and Pb(II), which are known to interfere with other previously suggested electrodes. The proposed membrane electrode was used as a sensor for determining the Cu(II) content in black tea samples. It was also applied as an indicator electrode in the potentiometric titration of Cu2+ ions with EDTA.