Fluorescent probes bearing a reactive moiety of 1,1-dicyanovinyl are known to detect several biological species including bisulfite and hypochlorous acid, which, however, possess a selectivity issue among those analytes. Structural modifications of the reactive group for optimal steric and electron effects based on theoretical calculations led us to address the selectivity issue, offering new reactive moieties that provide complete analyte selectivity, including that between bisulfite and hypochlorous acid, in cells as well as in solution.