A fluorescent Zn(2+) sensor 2-(hydroxymethyl)-4-methyl-6-((quinolinyl-8-imino)methyl)phenol (HMQP) based on the 8-aminoquinoline platform has been synthesized. This sensor displays high selectivity, sensitive fluorescence enhancement, strong binding ability, and ratiometric response to Zn(2+) in Tris-HCl (50 mM, pH 7.54), THF-H(2)O (9:1, v/v). And an obvious color change between HMQP and Zn(2+)-MQP(-) can be visually observed by the naked eye. The composition of the complex Zn(2+)-MQP(-) has been found to be 1:2 based on the fluorescence/absorption titration and further confirmed by X-ray crystallography.