||Mercury is a highly poisonous element and widespread pollutant, occurring from natural and anthropogenic sources. Organic forms of mercury, typically, methylmercury species (CH3HgX; X = halides, etc.) are much more toxic than inorganic mercury species because of their lipid solubility. In this work, we have designed three dansyl-based “turn-on” fluorescent probes which showed remarkable enhanced fluorescence intensity in the presence of Hg2+ and CH3Hg+. This fluorescent probes specific for mercury and methylmercury ions were synthesized on the basis of displacement reaction of arylboronic acid with mercury species. All three probes showed high selectivity towards Hg2+ and CH3Hg+over a wide range of metal ions in aqueous buffer solution. One of the probes exhibited promising fluorescent sensing property because of its high sensitivity and fast response.