3-trimethylsilyl-1-arylcyclobutyl carbocations, 10 and 11, where the cross-ring 3-trimethylsilyl group has the potential to interact with the cationic center, have been generated under solvolytic conditions. When the cationic center can interact with the rear lobe of the carbon–silicon bond, rate enhancements become progressively larger as the substituent on the aryl group becomes more electron-withdrawing