Triangular 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and linear tetrafluorophthalonitrile (TFPN) or 2,3,5,6-tetrafluoro-4-pyridinecarbonitrile (TFPC) were linked by 1,4-dioxin linkages to form crystalline 2D covalent organic frameworks, termed COF-316 and -318. Unlike the condensation reactions commonly used to crystallize the great majority of COFs, the reactions used in this report are based on nucleophilic aromatic substitution reactions (SNAr) that are considered irreversible. Our studies show that the reactivity of TFPN and TFPC with HHTP is enhanced...