We highlight our recent achievements in the design of fluorescent dyes for the investigation of chemical reactions on the single-molecule level. These fluorophores are tailored to undergo changes in their photophysical properties upon chemical transformations. Three examples are presented: electrophilic aromatic substitution, phosphoester cleavage, and oxidation of double-bonds. Thin-layer chromatography and fluorescence correlation spectroscopy are used to separate and characterize the different reaction products, respectively. We are planning to develop more fluorescent synthons which enable us to perform single-molecule chemistry of various reactions.