We report a difluoroboradiaza-s-indacene (BODIPY) dye substituted with bis(methoxycarbonyl)ethenyl at 3 and 5 positions as a near-IR colorimetric and fluorometric "on-off' pH sensor. The sensor absorbs and emits light at ca. 600 nm with high absorbance and fluorescence intensities (log(epsilon) = 5.0, phi f = 0.77 in ethanol) and basification causes dramatic changes on these optical properties. The sensor reversibly responses to pH changes between 7.0 and 10.0 in ethanol/water and can easily be synthesized from 1,9-diformyldipyrromethane with a one pot procedure. (C) 2015 Elsevier Ltd. All rights reserved.