A rational design and synthesis of covalent organic frameworks (COFs) displaying efficient adsorption of surrogates for common organic pollutants is demonstrated herein. Significantly, the top performing mesoporous triazine-functionalized polyimide COF exhibits superior adsorption of the small dye molecule methylene blue, achieving a maximum adsorption capacity of similar to 1691 mg g(-1) (similar to 169 wt %), surpassing the performance of all previously reported nanoporous adsorbents. The experimental results and accompanying in silico simulations suggest that both the size of the organic dye molecules and the intrinsic pore-size effect of the COF material should be taken into account simultaneously for the construction of COF-based adsorbents with efficient dyes adsorption capacities. The structural diversity of COF materials along with the understanding of the encapsulation of organic dyes on COFs holds great promise for developing novel COF adsorbents for the efficient removal of organic pollutants from wastewater. (C) 2017 American Institute of Chemical Engineers AIChE