Electronic supplementary information For A Heptamethine cyanine -Based Colorimetric and Ratiometric Fluorescent Chemosensor for Selective Detection of Ag + in an Aqueous Medium Hong Zheng * , Min Yan, Xiao-Xing Fan, Dan Sun, Shi-Yao Yang, Li-Jiao Yang, Jun-Dong Li, Yun-Bao Jiang* Department of Chemistry, College of Chemistry and Chemical Engineering, and the MOE Key Laboratory of Analytical Sciences, Xiamen University, Xiamen 361005, China. E-mail: hzheng@xmu.edu.cn , ybjiang@xmu.edu.cn Tel: +86 592 2180307; Fax: +86 592 2186731 Instruments and Materials NMR spectra were recorded on Bruker AV400 NMR and Bruker AV300 NMR. Mass spectra were measured with a JEOL JMS-T100LC mass spectrometer (ESI+). HR-MS spectra were measured with a Bruker En Apex ultra 7.0T FT-MS mass spectrometer. Uncorrected fluorescence emission spectra were conducted on a Hitachi F-4500 luminescence spectrometer. Absorption spectra were determined on a Varian CARY 300 spectrometer. Doubly distilled water was used throughout the experiments. All the materials for synthesis were purchased from commercial suppliers and used without further purification. General detection procedures. Compound 1 was dissolved in CH 3 OH to make a 1.0×10 -3 M stock solution, which was further diluted to required concentration for measurement. Silver nitrate was dissolved in water to make a 1.0×10 -3 M stock solution of silver ion. Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2012