A highly selective and sensitive chromogenic and fluorogenic dual signal responding fluoride-sensor 1, comprising a Ru-bipy fluorophore (bipy = 2,2′-bipyridine) and a 2,4-dinitrophenylhydrazone chromophore was prepared and spectroscopically characterized. Uv-vis titrations with F⁻ revealed the appearance of a new intense absorption band centered at about 580 nm which was accompanied by a dramatic change in color from yellow to magenta, with the association constant logK being 6.71 ± 0.04. Fluorescence spectra showed that upon addition of F⁻, the emission intensities enhanced significantly without any change in the excited and emission wavelengths, suggesting a potential photoinduced electronic transfer (PET) signaling transduction mechanism. An easy-to-prepare test paper which was obtained by putting a filter paper into an acetonitrile solution of 1, can detect F⁻ in aqueous media, indicating the potential application for detecting F⁻ in natural aqueous environments without any spectroscopic instrumentation. Spectroscopic titrations of the free ligand were also studied for comparison.