Siloxane and benzimidazole polymers containing carborane groups were synthesized and their thermal stability was measured. The data show the stabilizing effect of the carborane group on the thermal and oxidative stability of the polymer. In many instances the increase in thermal stability has been attributed to the inductive effect of the carborane group. In one case the oxidative stability of a silicone polymer has been increased by a carborane group adjacent to the silicon atom carrying the methyl groups. Carborane in the backbone of a silicone polymer appears to have inhibited rearrangement to cyclic compound. Metal panels coated with carborane polymers appear to have outstanding stability, apparently due to the formation of a protective film during the heating cycle.