We employed alcohols as initiators for living cationic polymerization of vinyl ethers and p-methoxystyrene, coupled with tolerant Lewis acid, borontrifluoride etherate (BF3OEt2), although they were known to be poisonous reagent to bring about chain-breaking such as chain transfer/termination rather than such beneficial one for propagation and polymerization-control. As well known, without assistance of additive, ill-defined polymers with broad molecular weight distributions (MWDs) were produced. Even addition of conventional oxygen-based bases, for example, ethyl acetate (AcOEt), 1,4-dioxane (DO), tetrahydrofran (THF), and diethyl ether (Et2O) was less efficient in this system to control molecular weights and MWDs (M-w/M-n > 2.0). In contrast, by addition of dimethyl sulfide (Me2S), MWDs of the resultant polymers became much narrower (M-w/M-n < 1.23) and the number-average molecular weight (M-n) increased in direct proportion to monomer conversion in agreement with the calculated values assuming that one alcohol molecule generates one polymer chain. Studying changed feed-ratio of alcohol to monomer and structural analyses with NMR and MALDI-TOF-MS indicated that quantitative initiation from alcohol giving alkoxide counteranion. This system opens a new way to use a variety of alcohols as initiators, which would allow us to design variety of structures and functions of counteranion. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4194-4201, 2009