A novel Schiff base-based sensor (L) has been designed, synthesized, and developed as a fluorescent and colorimetric sensor for cyanide and acetate. This L exhibited a quick response with rapid sensitivity to CN– and AcO- through a remarkable color change from yellow to red which was detectable by the naked eyes. It also sensed CN– and AcO- in a fluorescent way via an enhancement in fluorescence intensity. The interaction between L and anions (CN– and AcO-) was investigated by using UV–Vis studies, and 1H NMR titration. The theoretical DFT calculations were also employed to support the results, which displayed good agreement with the experimental value acquisition. As the detection limit for cyanide and acetate were 2.1 × 10-9 M and 1.7 × 10-9 M; respectively, low concentrations of these anions could be detectable in the proposed L sensor. In addition, L showed significant reversibility of CN– detection by using Cu2+ as a proper reagent with two different sensing methods including color change and UV–Vis. Last but not least, L could be applied to rapidly detect CN– in a wide range of pH. As a result, the proposed sensor is promising to identify cyanide and acetate in practical applications in medical, biological, and chemical fields.