Luminescent Tb³⁺ functionalized metal–organic frameworks (MOFs) are prepared and act as food preservatives sensor and water scavenger for NO₂–. Classical metal–organic frameworks with uncoordinated N atoms in pores are elected as carrier to encapsulate Tb³⁺ ions. This Tb³⁺ incorporated material reveals excellent characteristic green luminescence of Tb³⁺ and good fluorescence stability in water. Subsequently, we choose this probe for sensing NO₂– among several food preservative compounds, showing a highly sensitive capability for detection of NO₂–; it is then proved that the Dexter energy transfer (DET) causes the luminescent quenching between Tb³⁺ and NO₂–, achieving the detection of NO₂–. This probe is also employed to detect the NO₂– in real water samples and act as water scavenger to remove the NO₂– in drinking water, showing a good removal capacity 3.45 mg (75.0 μmol) of NO₂– per gram of particles.