EMT zeolite-encaged molybdenum oxynitride clusters were prepared by several methods, leading to different dispersions of the molybdenum species. HRTEM and EDX measurements indicated that, when the molybdenum species were inside of the zeolite porosity, they were homogeneously dispersed in the form of clusters whose diameters were less than 10 Angstrom. Depending on the preparation, it was shown by X-ray diffraction and specific surface area measurements that the EMT zeolite crystallinity was affected to different extents following ammonia treatments used for nitridation. The catalytic behavior of these nitrided compounds was studied in the n-heptane conversion. Supported on NaEMT, the encaged molybdenum oxynitride showed a reactivity of a bulk material. The most active catalyst was the low-temperature (523 K) catalyst, the n-heptane isomerization appearing as the main reaction. In contrast, for the catalysts supported on acidic HEMT, n-heptane cracking was mainly observed and the deactivation of the Mo-oxynitride supported catalysts was lowered compared to that of HEMT alone.