The　sustainability　of　uranium-based　nuclear　energy　relies　on　the　development　of　quick　and　effective　uranium　adsorbents.　Herein,　we　propose　a　facile　post-synthetic　technique　by　grafting　amino-functional　groups　onto　the　fluorenone-functionalized　conjugated　microporous　poly(aniline)s　(CMPs)　network　to　acquire　a　novel　class　of　N　decorated　polymers　for　uranium　capture.　By　leveraging　the　abundant　N　sites　and　microenvironment-containing　molecular　structure,　CMPA-F-BDA　showcases　excellent　UO22+　adsorption　performance　with　fast　adsorption　kinetic　with　initial　adsorption　rate　up　to　43.78　mg　g−1　min−1,　Langmuir　adsorption　capacity　of　443　mg　g−1　and　exceptional　adsorption　selectivity　of　Kd　=　1.3　×　107　mL　g−1　even　in　the　serious　presence　of　competitive　cations.　Additionally,　CMPA-F-BDA　could　treat　up　to　18.5　L　g−1　of　low-concentration　uranium　solution　(1　mg　L−1)　and　actual　seawater,　removing　87.9%　of　uranium　from　10　L　of　seawater,　and　has　excellent　reusability.　This　study　demonstrates　the　bright　future　of　CMPs　for　the　extraction　of　low-concentration　uranium.　©　2024　Elsevier　B.V.