tert-Butoxybenzenes including the 4-substituted derivatives of anisole, toluene and p-chlorobenzene have been synthesized and studied as initiators in combination with TiCl4 for polymerization of isobutylene (IB) in CH2Cl2/methylcyclohexane (MeCHx) solvent mixtures at -78 degrees C, Living polymerizations with slow initiation were observed by the all-monomer-in (AMI) and incremental monomer addition (IMA) techniques, and polymers with narrow molecular weight distribution (MWD) (M(W)/M(n) < 1.1) were obtained under certain conditions, Aging of the initiating system prior to charging the monomer does not improve the initiating efficiency, It has been found that the initiating efficiency can be increased by increasing the solvent polarity, however, the relative volume of CH2Cl2 is limited in order to avoid polymer precipitation and bimodal MWD.