Transalkylation is the transfer of an alkyl group from one organic molecule to another, producing a new pair or distribution of alkylated and dealkylated products without changing the total number of alkyl groups in the reacting system. In aromatic chemistry, an alkylbenzene acts as the alkyl donor and another aromatic ring as the acceptor, commonly on a Brønsted-acidic zeolite through carbocationic or surface-bound alkyl intermediates ^[1]. The process interconverts mono-, di-, and trialkylbenzenes, and product distributions reflect alkyl-transfer equilibria, aromatic substitution selectivity, pore topology, and acid-site accessibility ^[2]. It differs from simple alkylation, which introduces an alkyl group from a distinct alkylating reagent, and from dealkylation, in which the removed group is not transferred to an organic acceptor. Disproportionation is the special case in which two molecules of the same alkylated compound exchange groups to yield less- and more-substituted products.