The optical behavior of a simple intramolecular charge transfer (ICT) fluorescent probe, a coumarin-nitrobenzene conjugate (CNB), has been described to detect cyanide (CN⁻) selectively in buffered aqueous media. The cyanide addition on the electron-deficient alkene bridge interrupts the π-conjugation in CNB, which obstructs the ICT process and results in a color change from yellow to colorless and a significant fluorescence enhancement at 410 nm. Job's plot analysis revealed a 1 : 1 stoichiometry for the interaction between the probe and cyanide anion with a detection limit of 0.14 μM. The probe was also used for fabrication of test strips that could be used in practical and efficient CN⁻ test kits.