In this study, pH on-off fluorescent chemosensors based on indeno-furan derivatives have been designed, synthesized and characterized. The designed sensors were based on the change in structure of phenazine/ quinoxaline unit and keeping indeno-furan as common unit. These compounds exhibit pH dependent on/off fluorescence and thus act as fluorescent pH sensors. The change in fluorescence of 3a and 3b is reversible within the wide pH range of 2-11. The color change of these sensors could also be detected by naked eyes thus making them promising candidates as colorimetric pH indicators also. (C) 2015 Elsevier B.V. All rights reserved.