Ciprofloxacin (CIP) is a commonly used antibiotic, but its abuse may cause bacterial resistance, posing a high risk to the environment and human health. Herein, based on the molecular imprinting technology, this study proposed a ratiometric fluorescence sensor employing the "post-doping" strategy, which aims to be rapid, selective, and visually easy-to-use for CIP detection to address antibiotic residues and environmental risks. Specifically, by exploiting the "antenna effect" of lanthanide metal ions (Ln