Pyridine adsorption monitored by FTIR spectroscopy revealed germanosilicate UTL type zeolite to contain intrinsic Bronsted acidity required for catalytic activity. Germanosilicate UTL type zeolite was converted into a bifunctional catalyst and evaluated in n-decane isomerization and hydrocracking. To assess the stability of the framework during catalyst preparation and use, three different strategies of converting the zeolite into bifunctional catalyst were followed: incipient wetness impregnation with Pt(NH3)(4)Cl-2 solution before and after evacuation of the template by calcination, and physical mixing of calcined UTL with Pt-containing amorphous silica. All three samples showed catalytic activity but to very different degrees. The possibility of structure degradation during catalyst preparation and catalysis was investigated by XRD and Si-29 MAS NMR. The impregnation of as-made germanosilicate UTL zeolite with platinum and pretreatment in the reactor led to superior stability and activity. The n-decane test previously was used to probe zeolite micropore architectures with 8-, 10-and 12-membered rings. Its validity is now extended to the extra-large pore zeolites. The linear trend of increasing ethyloctane vs. methylnonane selectivity with increasing pore size has now been confirmed also for UTL with 14 membered rings.