This paper reports the synthesis of a sp² carbon-conjugated fluorescent covalent organic framework (COF) named TFPT-BTAN-AO, exhibiting excellent chemical, thermal, and radiation stability. TFPT-BTAN-AO demonstrates a high UO₂²⁺ adsorption capacity (427 mg g⁻¹) due to abundant uranium-binding groups within its open 1D channels. It also features a rapid response time (2 s) and a low detection limit (6.7 nM UO₂²⁺), making it suitable for real-time UO₂²⁺ monitoring and extraction. The study highlights the potential of fluorescent COFs for radionuclide detection and extraction, with the strategy applicable to other contaminants through ligand design.