A new fluorescent sensor based on a benzimidazole unit bearing bis(ethoxycarbonylmethyl) amino groups was designed and synthesized. The ligand exhibits strong sensitivity and selectivity for Ag + by enhanced fluorescent intensity in the presence of a wide range of other tested metal ions in methanol. The colorimetric and fluorescent response to Ag + can be conveniently detected even by the naked eye, which offers a facile method for visual detection of Ag + .