Nanoporous crystalline aluminosilicates, zeolites, are synthesized by solvothermal method producing three-dimensional (3D) crystals.An alternative, more controllable approach of zeolite synthesis - assembly-disassembly-organization-reassembly (ADOR) - can be used for preparation of isoreticular zeolites with tuneable porosity.Zeolites porosity allows their wide use as isomerization catalysts due to their shape selectivity effects.Selective isomerization of m-xylene towards p-xylene is an industrially important reaction due to a high demand for the latter as a substrate for terephthalic acid productionIn this work, the effect is investigated of pore size (shape selectivity effect) on the isomerization of m-xylene using a system of isoreticular Al-containing zeolites.These materials, prepared by ADOR approach (UTL, IPC-7, IPC-2, IPC-6, and IPC-4) had different layers connectivity, and various channel systems.The effect is tracked of the pore systems of ADOR zeolites (8-14-ring channels) on the catalytic performance in gas-phase m-xylene isomerization.The crystallinity, interlayer distances, phase purity, and textural properties are investigated of the prepared materials, their crystals morphol., and aluminum content.M-xylene isomerization was carried out in a fixed-bed reactor at 350°.The ADOR catalysts were compared with standard ZSM-5 zeolite.It is shown that the dependence of zeolite porosity on the performance in isomerization of m- to p-xylene.Smaller pore zeolites: IPC-4 (8- and 10-ring channels) and IPC-6 (8-, 10- and 12-ring channels) exhibited the lowest conversions, while the highest conversion and p-xylene yields were observed for IPC-2 (10- and 12-ring channels).The presence of extra-large, 14-ring channels (IPC-7 and UTL) resulted in the drop of selectivity due to the xylene disproportionation.