A colorimetric and ratiometric fluorescent probe 2-([1, 1 ' -biphenyl]-4-yl)-2, 3b,11a,11b-tetrahydro-1Himidazo[4,5-f][1,10]phenanthroline (probe 1 ), was designed and synthesized for sensitive and selective detection of Zn 2 + and Cd 2 + in methanol, test paper and actual water samples. When probe 1 was excited at 350 nm in methanol solution, in the presence of alkali metal ions, alkali-earth metal ions and a variety of transition metal ions, it showed sensitive fluorescence selectivity to Zn 2 + and Cd 2 + . With the addition of Zn 2 + , the color of the solution changed from purple to green with the naked eye, and with the addition of Cd 2 + , the color of the solution changed from purple to cyan. The fluorescence intensity of probe 1 showed a good linear relationship with Zn 2 + and Cd 2 + concentrations, and the detection limits of both Zn 2 + and Cd 2 + were 0.11 mu M. The binding mode of probe 1 and Zn 2 + was discussed according to the 1 -Zn single X-ray crystal structure. In addition, the results of strip test and real water sample test showed that probe 1 has potential application prospect in environmental ion recognition. (c) 2022 Elsevier B.V. All rights reserved.