The ignition behavior of 2,5-dimethyl furan (2,5-DMF), iso-octane, and their blends is investigated. To confirm that 2,5-DMF is the least reactive furan, its ignition behavior is compared with that of the isomer, 2-ethyl furan (2-EF), revealing the very high reactivity of 2-EF. For the 2,5-DMF/iso-octane comparative study, ignition delay times are measured over a temperature range from 1009 to 1392 K and pressures up to 12 atm for lean, stoichiometric, and rich mixtures of fuel, oxygen, and argon. It is observed that 2,5-DMF generally has longer ignition delay times than iso-octane when the equivalence ratio phi, the argon-to-oxygen ratio D, and pressure p are kept constant over a range of temperatures, T. Further, ignition delay times of a 2,5-DMF/iso-octane 50% blend (by liquid volume) are measured and compared to those of the pure fuels at stoichiometric and rich conditions and pressure of 12 atm. The blend shows intermediate reactivity between the pure fuels, albeit in closer alignment with iso-octane than 2,5-DMF. A combined model for 2,5-DMF and iso-octane combustion is developed, drawing from recent literature models for the pure components. Further modifications are carried out to improve agreement with the current and previous ignition data. The resulting model captures the ignition trends of the pure and blended fuels. Reaction pathway analysis and species sensitivity analysis are performed for more insight on the governing chemical kinetics. The reported experimental data set and the model advance combustion modeling of bio and conventional fuel blends for spark ignition engines. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.