The cationic homopolymerizations of N-vinylcarbazole 1-methoxy-1,3-butadiene, isobutyl vinyl ether, p-methoxystyrene, and cyclohexene oxide using three m,m’-dimethoxybenzyl esters as initiators have been investigated under both photochemical and dark conditions. The comparison between the thermal polymerization and photopolymerization rates revealed that these initiators work mainly via a photocationic initiating mechanism. Only N-vinylcarbazole produced high molecular weight polymer; the other monomers produced only low molecular weight polymers (10(2)-10(3)). The order of the reactivity of these initiators is m,m’-dimethoxybenzyl 2,4,6-triisopropylbenzenesulfonate (DMB-TIBS) > m,m’-dimethoxybenzyl m-nitrobenzenesulfonate (DMB-NBS) > m,m’-dimethoxybenzyl tosylate (DMB-T). Changing initiator concentration and reaction temperature affected the polymerization yield but had little influence on the polymer molecular weight. Increasing the monomer nucleophilicity and the stability of the formed counterions enhanced the polymerization rate and raised the product molecular weight. A photochemical initiation mechanism was suggested for these systems.