Herein, we report a facile approach towards the construction of poly-functional porous organic polymers (POPs). The functional groups employed were selected to span the range of Lewis-base to neutral to Lewis-acid character. Our results underline the effect of chemical functionality on the observed Q st for CO 2 adsorption inside the material, being largest for functional groups with electron donating O-and N-centered Lewis base sites. Our systematic investigation within a family of POPs revealed a wide range for CO 2 heat of adsorption (23.8–53.8 kJ mol À1) that is clearly associated with the chemical nature of the functional groups present. In addition, post-synthetic modification of POPs reported herein demonstrated a facile pathway to dramatically enhance carbon dioxide uptake energetics.