The mechanism of cationic polymerization of styrene monomers leading to well defined polymers proposed by Yang, Li and Stover is criticized. The growth does not occur on the ''colorless nondissociated ion pair'' represented as polarized covalent species but includes dynamic equilibration between covalent species and carbocations. In addition, ligand exchange between 1-phenylethyl bromide and SnCl4 leads to the formation of Lewis acids with much more labile Sn-halide bonds. The observed colors are due to the generation of side products, presumable indanyl cations, and not to the alleged propagating free ions.