AbstractThe polycondensation reactions of benzyl chloride, α‐chloroethylbenzene, and benzhydryl chloride in the presence of SnCl4 or AlCl3 as catalysts have been investigated in the temperature range between +80° and −135°C. Polycondensations of benzyl chloride and α‐chloroethylbenzene are quite similar in the reaction kinetics and are thought to occur by the same displacement mechanism. Polycondensation of benzhydryl chloride, however, seems to involve the formation of benzhydryl carbonium ions. At low temperatures linear polymers tend to be formed, in contrast with branched polymers produced at room temperature. Steric effects are found to play a major role in protecting polymers from branching at lower temperatures.Polybenzyl polymers are found to be less linear than poly(‐α‐methylbenzyl), even when prepared at −135°C.