Chiral fluorescent boronic acid 1 was found to be a highly enantioselective, chemoselective, and sensitive sensor for sugar acids, such as tartaric acid. Enantioselectivities (K-R/K-S) of up to 550:1, chemoselectivity up to 11000:1, and sensitivities in the micromolar range with sensor 1 were observed. Single-crystal X-ray analysis was used to confirm the structure of the fluorescent species.