The performance of calcium oxide particles produced from the decomposition of calcium-enriched bio-oil (CEB), the product of the reaction of bio-oil and calcium hydroxide, as a sorbent for the in situ removal Of SO2 and H2S from the flue gases of coal combustors and the coal gas produced in coal gasifiers, respectively, is investigated. Reactivity evolution experiments are carried out in a thermogravimetric analysis system using CaO samples prepared through decomposition of calcium-enriched bio-oil applied as a thin coating on a quartz pan or through calcination of two naturally occurring calcitic solids of high CaCO3 content. CEB is converted to CaO in one or two steps, that is, first conversion to CaCO3 in the presence Of CO2 and then calcination. Calcination and sulfidation or calcination and sulfation are carried out both sequentially and simultaneously. Because of its high porosity, the CaO material that results from the decomposition of CEB is found to be capable of reaching much higher conversions during sulfation than calcium carbonate calcines, with ultimate conversions that can be almost 100%. This material exhibits higher reactivities also during sulfidation, but all calcined materials can reach conversions close to 100% in this reaction because of the absence of pore plugging phenomena. However, because of the much faster calcination of the CEB-derived CaCO3, there is minimal interference between its calcination and sulfidation in the simultaneous process, while this is not the case for calcium carbonate solids.