A quinoline-based fluorescence sensor QDTD was developed for Zn2+. QDTD can detect Zn2+ by fluorescence turn-on. Detecting limit (0.27 mu M) of QDTD for Zn2+ was far below WHO standard (76.0 mu M). For the practical application, compound QDTD could be used to determine Zn2+ in real samples and applied to the test kit. More importantly, QDTD was expertly applied for Zn2+ imaging in HeLa cells and zebrafish with good membrane-permeability. Detection mechanism of Zn2+ ion by compound QDTD was suggested through the analytical tools like (HNMR)-H-1 titration, ESl-MS, Job plot, fluorescent and UV-vis titration, and theoretical calculations, and through the synthesis and applications of a model compound AAQA. (C) 2019 Elsevier B.V. All rights reserved.