Sensors bind to Cu2+, indicated by fluorescence quenching and color changes. Sensors are Cu2+ “visual-eye” indicators by color changes from yellow to orange. Sensors show high Cu2+-selectivity with low detection limits of 0.23 and 0.43 ppb. Sensor was applied to FIA system for rapid determination of 32 samples h−1. Sensor was used for imaging of HepG-2 cellular system.