Four kinds of mannitol-based ketal-linked porous organic polymers (MKPOPs) were successfully synthesized through condensation reaction between aromatic acetyl monomers and mannitol, catalyzed by p-toluenesulfonic acid. The structure of resulting polymers was confirmed by Fourier transform infrared and solid-state C-13 nuclear magnetic resonance spectrum measurements. The porosities of MKPOPs were investigated by gas adsorption experiments and the results indicate high carbon dioxide uptake (up to 11.5 wt% at 273 K and 1.0 bar) for MKPOPs due to the predominant microporous and hydroxyl-rich structures. Remarkably, MKPOPs exhibit excellent selective adsorption performances for carbon dioxide over methane (9.9-14.2, IAST at 273 K and 1.0 bar). These studies are of significant importance for MKPOPs and their potential application in selective gas adsorption. (C) 2016 Elsevier Ltd. All rights reserved.