Radical chain end functionalization of polystyrene previously prepared by NMP Using the SG1 nitroxide was investigated. Hydroxy-functional polystyrenes were easily prepared by two different pathways: via all exchange with TEMPO nitroxide followed by I Zn/AcOH reduction or via it radical hydroxylation Using the in situ preparation/reduction of the corresponding hydroperoxide, The introduction of it bromine end group was performed by radical bromination under mild conditions Using ethyl 2-bromoisobutyrate as bromine transfer agent. The latter polymer was further reacted with NaN3 and also Used its it macroinitiator to prepare PS-b-PMMA by ATRP to confirm the chemical post-transformation. Azide-functional polystyrenes were also prepared by it one-step radical azidation reaction using ethanesulfonyl azide. In all cases, the chemical transformations were followed by both liquid chromatography at the critical condition in pure eluent and Maldi-Tof MS.