A novel trichromophoric molecular chemosensor Rh–NI-Hz was designed, synthesized and examined for pH detection. It exhibited naked eye observed colorimetric and fluorometric responses to lower and high pH values. The probe sensitivity towards an acidic environment was achieved through the rhodamine part of the molecule where the colour was changed from colourless to red and yellow fluorescence was emitted. On the other hand, in a basic environment, the colour was changed to yellow and a green fluorescence emission was produced. Moreover, the probe mimics a digital comparator by executing three INHIBIT logic gates using H⁺ and HO⁻ as chemical inputs.