A number of coal-metal oxide systems were examined for a thermochemical CO2 gasification of coal in a two-step cyclic redox mode, as well as in a normal single-step mode for the purpose of utilizing solar high-temperature heat below 1173 K. In the two-step cyclic redox mode, metal oxide was reacted with coal powder as an oxidant in the absence of CO2 at 1173 K to produce CO, H-2, and the component metal which was reoxidized with CO2 to generate CO at lower temperatures in a separate step. In2O3 was found to be the most reactive metal oxide among the thermodynamically promising metal oxides. The two-step cyclic CO2 gasification could be repeated using the In2O3/In redox system by resupplying the consumed coal to the system. About 80% of the coal supplied to the system was gasified at the temperature range of 1023-1173 K. The In2O3 phase was completely regenerated without the formation of other solid phases after repeating the two-step gasification. In a normal single-step, continuous feeding mode of CO2 at a constant temperature of 1173 K, the coal-In2O3 system also showed the most reactivity for the Boudouard reaction of C + CO2 --> 2CO in the CO2 gasification of coal at the metal content of 17 wt % in the coal and metal oxide mixture. Depending on the indium content in the mixture, the initial coal-conversion rates with the coal-In2O3 system were 2.5-4 times as fast as that in the coal-CO2 reaction without any catalysts. The separation of used In2O3 from the remaining coal ash by In2O evaporation was also proposed.