A new imidazole-containing disubstituted polyacetylene (P1) with strong green fluorescence was successfully prepared through polymer reaction, which was nearly impossible to be obtained from the direct polymerization of its corresponding monomer. The polymer was soluble in common organic solvents, and its strong green fluorescence could be quenched completely by the Cu2+ and Co2+ ions, at the concentrations as low as 1.33 and 1.67 x 10(-5) mol/L (0.85 and 0.92 ppm), respectively. Because of the high stability of the complex formed by cyanide and copper ions, the quenched green fluorescence of P1 by copper ions could be turned on upon the addition of trace cyanide (as low as 2.70 x 10(-5) mol/L, 0.70 ppm), making P1 a new sensitive cyanide chemosensor. The results thus provided a new opportunity to develop anion chemosensors based on good cation chemosensors. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8070-8080, 2008