The α,ω-dihydroxy-terminated polystyrene (PS) was synthesized using a combination of atom atom transfer radical polymerization (ATRP), nucleophilic substitution, and click chemistry. Gradient polymer elution chromatography (GPEC) analysis techniques was used to precisely characterize the functionality of polymers. It was observed that elution behavior of α, ω-dibromo-PS was similar to that of the α, ω-diazido-PS, which indicate their similar interaction with the stationary column. The results show that the second click reaction on a PS chain is approximately three time slower than the first reaction.