A π-conjugated cyanostilbene derivative of (Z)-2-(4-nitrophenyl)-3-(4-(vinyloxy)phenyl)acrylonitrile (CN-vinyl) had been designed, synthesized and confirmed by the standard spectroscopic analyses. CN-vinyl possesses an unusual high emissive aggregation-induced emission (AIE) feature in a tetrahydrofuran/water mixture (2:8, v/v). The fluorescence intensity of CN-vinyl can be quenched linearly with the addition of Hg 2+ in a range of 0–50μM with a correlation coefficient of R 2 =0.9957. The detection limit of Hg 2+ is 37nM. The mechanism for Hg 2+ -mediated optical properties of CN-vinyl is due to the selective cleavage of vinyl group by Hg 2+ . Accuracy of the proposed methodology was evaluated by means of the recovery study in real samples and the analyzing certified reference material of the standard solution of Hg 2+ . By this novel strategy, CN-vinyl can be used for quantitative detection of Hg 2+ as well as the presence of other physiological relevant metal ions.