Covalent organic frameworks (COFs) represent an emerged class of high crystalline porous polymers with well-defined periodic structures, which not only allows one to rationally design and tailor their chemical structures or topologies, but also readily manipulate them in various applications on the basis of establishing the essential structure-property relationships and understanding the related mechanism 1-3 . Among them, vinylene-linked organic frameworks (COFs) feature prominent stability and -electron communication, likely helpful for expanding the potential applications of COFs, in particular, in the field of semiconductor . Thermodynamically controlled Knoevenagel condensation is one of the most powerful tools in the formation of carboncarbon double bond linkage . Unlike those traditional dynamic covalent chemistry, such condensation involves the generation of active intermediates, such as, carbon anions, which is crucial for efficiently boosting chain growth and correcting defect through self-healing processes for a COF . Typically, an available monomer bearing aryl α-carbon atoms, has to be enough electron-deficient for enhancing the α-proton acidity and stabilizing the reactive intermediate, commonly achieved by the introduction of multiple electron-withdrawing moieties, such as cyano group, pyridyl nitrogen . However, these modifications normally means a tedious preparation and the utilization of toxic reagent (e.g. NaCN or CuCN), meanwhile, significantly constrains the accessible reaction sites of a monomer, severely limiting its linking modes. Correspondingly, on the basis of very few monomers, vinylenelinked COFs with hexagonal crystal system occupied the major ratio, and several single-pore orthorhombic skeletons were originating from the ditopic monomer 1,4-phenylenediacetonitrile . While, a monomer with more αcarbon atoms (≥ 4) suitable for Knoevenagel condensation could not be found so far. Pyridyl nitrogen-containing molecules are widely used in catalysis, supramolecular chemistry, and organic semiconducting materials, associated with their intrinsic Lewis basicity, substantial physical properties, and self-assembling behaviors . Knoevenagel reaction holds some merits in the preparation of vinylene-linked pyridine-based small molecules or linear conjugated polymers using methyl-substituted pyridine, due to low-cost, environmentally friendly reagents, less unidentified reactive intermediates, and only trans-alkene formation . Unfortunately, the mechanism of such traditional reaction seems never to be investigated.