The kinetics of hydrogen uptake by N-ethylcarbazole and carbazole, and the kinetics of H-2 release from their hydrogenated products, is reported. The hydrogenation of N-ethylcarbazole at 130-150 degrees C on Ru was well described by a network of first-order stepwise hydrogenation reactions. The hydrogenation of N-ethylcarbazole was significantly faster than the hydrogenation of: carbazole, and in both cases, >95% selectivity to the completely hydrogenated products, dodecahydro-N-ethylcarbazole and dodecahydrocarbazole, was achieved. The dehydrogenation of dodecahydro-N-ethylcarbazole at 101 kPa and 150-170 degrees C, proceeded to 100% conversion of the reactant over a Pd catalyst within 1 h. However, only 69% of the stored H was recovered due to a low selectivity to N-ethylcarbazole. In the case of dodecahydrocarbazole dehydrogenation at 101 kPa and 170 degrees C over the same Pd catalyst, 28% H-2 recovery was obtained due to the strong adsorption of the product carbazole oil the catalyst Surface that also resulted in a slower rate of dodecahydrocarbazole dehydrogenation compared to dodecahydro-N-ethylcarbazole.