Exploring the Catalytic Potential of Bioinspired Taurine‐Functionalized Carbon Quantum Dots as Bifunctional Catalysts for Diverse Sustainable Organic Transformations in Water

Abstract Taurine‐functionalized Carbon Quantum Dots (Tau‐CQDs) were synthesized and evaluated for their catalytic potential under metal‐, acid‐, and base‐free sustainable conditions, using water as a solvent for various organic transformations, including Knoevenagel condensation, the Biginelli reaction, and the Knoevenagel–Michael cascade. These bioinspired N, S‐doped CQDs exhibit bifunctionality, acting as hydrogen bond donors and acceptors for C−C, C−N, and C−O bond formation. Comprehensive characterization of the catalyst was performed using HRTEM, PXRD, XPS, FTIR, AFM, Zeta potential, UV–Vis, and photoluminescence spectrometry. The Tau‐CQDs demonstrated excellent reusability, maintaining catalytic performance over 10 cycles. Green chemistry metrics, including a low E‐factor, high atom economy, and favorable PMI, CE, and RME values, highlight this approach's environmental and economic advantages. Key properties, such as high reaction yields, short reaction times, water solubility, enhanced surface functionality, non‐toxicity, and mild operating conditions, underscore the broader significance of Tau‐CQDs as an efficient, sustainable catalytic platform. Additionally, the simple recovery of the catalyst via filtration, without the need for further purification, enhances its practical applicability.