Nature Communications, Published online: 26 May 2026; doi:10.1038/s41467-026-73712-x Heteropore covalent organic framework membranes have excellent uranium extraction capabilities, but their fabrication with well-defined hierarchical pores remains challenging. Here, the authors describe the pre-coating of covalent organic framework nanoparticles onto a nylon substrate as a general method for the preparation of heteropore covalent organic framework membranes.