Liquid–liquid equilibrium (LLE) experiments for the systems water + 2-methoxyphenol + MIBK and water + 1,2-benzenediol + MIBK were carried out at 303.15 and 328.15 K according to a procedure allowing the measurement of both the composition of the phases in equilibrium and their relative amounts. Binary LLE data of subsystems water + MIBK and water + 2-methoxyphenol were also measured, as was the solubility of 1,2-benzenediol in water. The experimental data were modeled using the NRTL activity coefficient model, with optimal energy parameters calculated from the experimental data. The NRTL model proved to be adequate in describing the LLE phase behavior of the systems investigated, and it can be used for the process design of liquid–liquid extraction of these aromatic solutes from aqueous phases. MIBK proved to be an efficient extractant for 2-methoxyphenol and 1,2-benzenediol, even though the distribution factors for 2-methoxyphenol are 4–5 times higher than those for 1,2-benzenediol. The results are relevant to the design of extraction processes aimed at recovering phenols from wastewater or aqueous phases produced in the hydrothermal conversion of biomass, such as in the case of the conversion of lignin, which is a byproduct of pulp mills and lignocellulosic bioethanol plants.