Aromatic conversion processes employing zeolite Y, zeolite omega and zeolite beta molecular sieve catalyst. A feed stock containing at least one aromatic compound and having water entrained therein is passed to a dehydration zone. In the dehydration zone, water is removed to provide a dehydrated feed stock of a water content no more than 100 ppm, preferably 50 ppm or less. The dehydrated feed stock is then supplied to the reaction zone containing the molecular sieve catalyst selected from the group consisting of zeolite Y, zeolite omega, and zeolite beta. The reaction zone is operated at temperature and pressure conditions to maintain the reactor contents in the liquid phase and also sufficient to cause the conversion reaction to proceed in the presence of the catalyst. Specific conversion processes include the ethylation of benzene under liquid-phase conditions to produce ethylbenzene and the transalkylation of a feed stock containing a mixture of a polyalkylbenzene component and a benzene component to produce a disproportionation product comprising a monoalkylbenzene.