A new conjugated polymer based on polyfluoreneethynylene has been synthesized by Sonogashira coupling reaction. Each repeat unit of the polymer contains two carboxylic acid groups which can selectively incorporate with Cu(2+) in methanol. The sensitivity was extremely high through an efficient fluorescence quenching process amplified by the polymer aggregation mechanism. Such polymer will be a good candidate of the new fluorescence sensors for Cu(2+) with good selectivity and high sensitivity. (C) 2008 Elsevier Ltd. All rights reserved.