A kind of fluorene-based conjugated polymer with tethered thymine (T) groups {poly[(9,9-dioctyl)-2,7-fluorene-{9,9-dioctyl-41,2,3-triazol-[5-(hydroxymethyl)tetrahydrofuran-2-yl]-5-methylpyrimidine-2,4(1H,3H)-dione}-2,7-fluorene]-co-[(9,9-dioctyl)-2,7-fluorene-4,7-bis(5-thiophen-2-yl)benzo-2,1,3-thiadiazole] (P-3)} was successfully synthesized by a Cu(I)-catalyzed click reaction between the acetylene-substituted polymer precursor {poly[(9,9-dioctyl)-2,7-fluorene-(9,9-dioctyl-4-phenylacetylene fluorene)]-co-[(9,9-dioctyl)-2,7-fluorene-4,7-bis(5-thiophen-2-yl)benzo-2,1,3-thiadiazole]} and 3-azido-3-deoxythymidine. The chemical structures of the intermediates and target polymer were verified by Fourier transform infrared spectroscopy and 1H-NMR analyses. The specific binding with Hg2+ of P-3 was corroborated by ultravioletvisible spectroscopy and photoluminescence analyses against other metal ions. The results show that P-3 possessed selectivity and sensitivity toward Hg2+. Around 77% of photoluminescence intensity of P-3 was quenched when the concentration of Hg2+ reached 7.7 x 104 M and with a detection limit in the range of about 4.8 M. A comparison experiment suggested that a synergic effect of the tethered T and S atoms interrelated with Hg2+ existed in P-3. Most of the fluorescence intensity of P-3 was recovered upon the addition of iodide anions to the P-3/Hg2+ complex; this suggested that P-3 could be used as a potential reversible optical Hg2+ probe. (c) 2013 Wiley Periodicals, Inc.