The alkylation of aromatic hydrocarbons with olefins is applied on a large scale in the chemical industry. The efficiency of these productions is highly improved performing alkylation combined with transalkylation, the latter allowing conversion of some low valued by-products such as polyalkylbenzenes into their monosubstituted homologues. The aim of this contribution is to summarize some examples of novel industrial processes, based on new catalysts that are environmentally friendly, for the production of ethylbenzene and cumene, two of the most important chemicals produced by alkylation/transalkylation.