Living cationic polymerization of styrene was achieved with a series of initiating systems consisting of a HX-styrenic monomer adduct (X = Br, Cl) and ferric chloride (FeCl3) in conjunction with added salts such as tetrabutylammonium halides (nBu(4)N(+)Y(-); Y- = Br-, Cl-, I-) or tetraalkylphosphonium bromides [nR'4PBr; R' = CH3CH2-, CH3(CH2)(2)CH2-, CH3(CH2)(6)CH2-] or tetraphenylphosphonium bromide [(C6H5)(4)PBr] in dichloromethane (CH2Cl2) and in toluene. Comparison of the molecular weight distributions (MWDs) of the polystyrenes prepared at different temperatures (e g. -25 degrees C, 0 degrees C and 25 degrees C) showed that the polymerization is better controlled at ambient temperature (25 degrees C). The polymerization was almost instantaneous (completed within 1 mm) and quantitative (yield similar to 100%) in CH2Cl2 In CH2Cl2, polystyrenes with moderately narrow (M-w/M-n similar to 1.33-140) and broad (M-w/M-n similar to 15-2.4) MWDs were obtained respectively with and without nBu(4)N(+)Y(-). However, in toluene, the MWDs of the polystyrenes obtained respectively with and without nBu(4)N(+)Y(-)/nR(4)'P+Br were moderately narrow (M-w/M-n = 133-15) and extremely narrow (M-w/M-n = 105-1.17). Livingness of this polymerization in CH2Cl2 was confirmed via monomer-addition experiment as well as from the study of molecular weights of obtained polystyrenes prepared simply by varying monomer to initiator ratio A possible mechanistic pathway for this polymerization was suggested based on the results of the H-1 NMR spectroscopic analysis of the model reactions as well as the end group analysis of the obtained polymer (C) 2010 Elsevier Ltd All rights reserved