Exceptional electron conduction in two-dimensional covalent organic frameworks

•Polycondensation enables designed synthesis of n-type organic/polymeric semiconductors•The frameworks reduce reorganization energy and induce interlayer electronic coupling•The achieve exceptional electron mobility•Electrons move in the framework lateral vertical directions In contrast to inorganic semiconductors, semiconductors usually have limited mobilities owing their structural nature. Enabling conduction with high carrier mobility is especially extremely challenging. Herein, we solve this problem by organizing electron-deficient isoindigo units form well-ordered yet non-conjugated covalent organic frameworks, constituting two-dimensional polygonal backbones ordered columnar ? arrays via face-to-face stack. Hall effect measurements, time- frequency-resolved terahertz spectroscopy, as well theoretical calculations, mutually corroborate high-rate transport band-like across layers over 2D planes undoped frameworks. This work thus offers a new regime high-performance semiconductors. 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