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• Selective colorimetric recognition of cyanide ion in both solution and solid states. • Fast response to CN– (< 5 s). • Water percentage has a key role in the cyanide's recognition mechanism. • Recognition mechanism was investigated by IR soectroscopy. A novel chemosensor based on Nifuroxazide Cr(III) complex was developed for recognizing CN– over other tested anions e.g., F–, Cl–, Br–, I–, CH 3 COO–, NO 2 –, PO 4 3–, and SCN– in DMSO–H 2 O (9:1, v/v) and THF. Without any interference from the tested anions, UV–vis spectroscopy was used to investigate the recognition of CN–. The deprotonated species that resulted from the ionization of the phenolic group may be the cause of the color shift that occurred after adding CN– to the solution of the Cr(III) complex. The charge transfer interaction between the electron-donor unit and the electron-deficient nitro-furan moiety was improved as a result of the ionization of the phenolic group. The fact that the developed color vanishes in protic polar solvents e.g., H 2 O, CH 3 OH, and C 2 H 5 OH may lend credence to this assumption. The Lambert–Beer's law was obeyed in the concentration ranges of 3.4 × 10−3–3.4 × 10−5 M and 1.0 × 10−4–5.0 × 10−6 M in DMSO–H 2 O (9:1, v/v) and THF, respectively, reflecting the significant role of the solvent in controlling the sensitivity of the developed probe. The electronic transitions were investigated by executing time-dependent density functional theory calculations. [Display omitted] [ABSTRACT FROM AUTHOR]