Covalent organic frameworks (COFs) are an emerging class of porous crystalline polymers with well-defined structures and tunable functionalities, which has fascinating applications in a wide range of fields. However, the synthetic procedures of COFs are mainly confined to solvothermal synthesis method which usually requires harsh experimental conditions. In this work, we develop an effective solvent-free synthesis method to construct a series of 2D COFs including imine-linked, azine-linked, β-ketoenamine-linked, which avoid the complicated solvent screening process and most of the disadvantages of solvothermal methods. The crystallinity and porosity of these COFs are comparable to those prepared by traditional solvothermal routes. What's more, the advantages of solvent-free method enable the production of gram-scale of those 2D COFs through one-pot reaction, demonstrating high industrial application potentials. This article is protected by copyright. All rights reserved.