Developing an effective method for the detection of nitrite (NO 2 À ) ions in the natural environment especially in environmental waters and soils is very necessary, since they will cause serious damage to human health once excess NO 2 À ions enters the human body. Therefore, a new colorimetric fluorescent probe NB-NO 2 À for determining NO 2 À ions was designed, which possesses good water-solubility and satisfactory selectivity over other common ions for NO 2 À ions. The addition of NO 2 À ions changed the color of solution from blue to colorless seen by the naked-eye. Furthermore, through test and calculation, the detection limit of the probe NB-NO 2 À is 129 nM. Based on the earlier excellent characteristics, the probe NB-NO 2 À was successfully used for monitoring NO 2 À ions in environmental waters and soils.