Processes are disclosed for production of value-added products from fluid admixtures of hydrocarbon compounds at least one of which is an aromatic hydrocarbon compound, by means of one or more devices using perm-selective polymeric membranes. More particularly, processes of the invention comprise separations using aromatic-selective polymeric materials comprising long-chain polymeric molecules in which recurring amide and imide linkages are part of the main polymer chain. Processes of the invention advantageously employ aromatic-selective membranes to separate an aromatic enriched stream from gaseous and/or liquid mixtures comprising one or more aromatic hydrocarbon compounds thereby producing a stream comprising the remaining compounds which may include alkenes and/or alkanes containing 3 or more carbon atoms, and/or alicyclic hydrocarbons. Processes of the invention are particularly useful for recovery of meta-xylene and para-xylene products from liquid mixtures even containing ethylbenzene as well as the three xylene isomers.