Module‐Patterned Polymerization towards Crystalline 2D sp2‐Carbon Covalent Organic Framework Semiconductors.

Despite rapid progress over the past decade, most polycondensation systems even upon a small structural variation of the building units eventually result in amorphous polymers other than the desired crystalline covalent organic frameworks. This synthetic dilemma is a central and challenging issue of the field. Here we report a novel approach based on module‐patterned polymerization to enable efficient and designed synthesis of crystalline porous polymeric frameworks. This strategy features a wide applicability to allow the use of various knots of different structures, enables polycondensation with diverse linkers, and develops a diversity of novel crystalline 2D polymers and frameworks, as demonstrated by using the C=C bond‐formation polycondensation reaction. The new sp2‐carbon frameworks are highly emissive and enable up‐conversion luminescence, offer low band gap semiconductors with tunable band structures, and achieve ultrahigh charge mobilities close to theoretically predicted maxima. [ABSTRACT FROM AUTHOR]