The effects of boronic acid on the fluoride-selective chemosignaling behavior of a merocyanine dye were investigated. In the presence of phenylboronic acid (PBA), N-methylquinolinium-based merocyanine dye displayed fluoride-selective chromogenic signaling behavior over other commonly coexisting anions in the micromolar concentration range. Signaling is produced by a fluoride-induced displacement of the dye from its complex with PBA, resulting in a significant chromogenic signal for the fluoride ion. This signaling was successfully analyzed using a ratiometric analysis of the UV-vis absorption in response to changes in fluoride ion concentration. A PBA substituted with an electron withdrawing group was found to exhibit a more pronounced signal. Polymer-bound PBA also exhibited useful fluoride-selective signaling behavior.