A new poly(p-phenylene ethynylene) derivative with pendant 2,2'-bipyridyl groups and glycol units (PPE-bipy) has been prepared, and its metal ion sensing properties were investigated. The polymer of PPE-bipy exhibited high selectivity for Hg2+ as compared with Li+, Na+, K+, Ba2+, Ca2+, Mg2+,Al3+, Mn2+, Ag+, Zn2+, Ph2+, Ni2+, Cd2+, Cu2+, Co,(2+) and Fe3+ in THF/EtOH (1:1, v/v) solution. The fluorescence of PPE-bipy was efficiently quenched by Hg2+ ions, and the detection limit was found to be 8.0 nM in a THF/EtOH (1:1, v/v) solvent system. PPE-bipy also showed a selective chromogenic behavior toward Hg2+ ions by changing the color of the solution from slight yellow to colorless, which can be detected with the naked eye. (C) 2008 Wiley Periodicals, Inc.