In this article, we successfully designed and synthesized a novel chemosensor PW bearing rhodamine B hydrazide and 8-formyl-7-hydroxyl-4-methylcoumarin, which displayed both colorimetric and “turn-on” fluorescence responses for CN− in DMSO/H2O (1 : 1, v/v, pH = 7.20) solution. The probe could distinguish CN− via a deprotonation process and the mechanism of intramolecular charge transfer (ICT), which was proved by 1H NMR titration, ESI-MS and DFT calculations. The detection limit of the sensor PW towards CN− was 1.592 × 10−7 M. Moreover, the sensor PW was successfully utilized to detect CN− in bitter almond. Test strips containing PW were also prepared, which could act as a colorimetric tool to detect CN− in practical application.
