Lysine-functionalized perylene was used to modify nanoparticles. Due to the benefits from a synergetic effect that originated between the perylene and silver nanoparticles, color-based metal sensor systems were established. At pH = 12.6, Cr⁶⁺ with a concentration of 100 nM could be detected by a color change from deep yellow to orange; after decreasing the pH to 12.0, the detection limit decreased to 2 μM. Interestingly, after further decreasing the pH to 11.0, another kind of metal ion (Cd²⁺) could be recognized with a detection concentration of 10 μM. At pH = 10.0, Pb²⁺ with a concentration of 2 μM could be detected.