An anthracene thiazole based Schiff base L was synthesized and employed for fluorescence switch-on detection of maleic acid in aqueous DMSO. The non-fluorescent L (10^–5 M) showed an instantaneous and selective fluorescence enhancement at 506 nm upon interaction with maleic acid (10^–5 M). Other potential carboxylic acids (10^–5 M), such as malic acid, citric acid, acetic acid, cinnamic acid, tartaric acid, succinic acid, fumaric acid, oxalic acid and malonic acid failed to alter the chromo-fluorogenic properties of L. Probe L can be employed to detect maleic acid down to 2.74 × 10^–6 M. The probe L showed good linearity from 2.97 to 6.87 µM. Analytical utility of L was examined by detecting maleic acid in various food additives and drosophila larvae.