<p>Rosocyanine, an inherently unstable curcumin–borate complex (CBC), has been primarily used in colorimetric assays for the detection of boron in soil, food, and water samples. Its limited chemical stability under ambient conditions currently hinders broader applications. In this work, the CBC was synthesized and stabilized using sustainable and eco‑friendly materials, extending its potential applications beyond analytical detection of boron. Because both curcumin and boric acid exhibit anticancer, antimicrobial, and antioxidant properties, enhancement of these properties is expected for the CBC once stability issues are overcome. To exploit such properties, we designed a tannic acid–polyvinylpyrrolidone (TA–PVP) nanocarrier system aimed at stabilizing Rosocyanine without compromising its bioactivity. Density functional theory and molecular dynamics simulations were employed to describe the stabilization of the CBC. Experimentally, the optical properties of the synthesized products were studied using UV–Vis and fluorescence spectroscopy, while the hydrodynamic diameter and surface charge of the particles were determined by dynamic light scattering and zeta potential measurements, respectively. Liquid chromatography–mass spectrometry and&#xa0;¹¹B nuclear magnetic resonance were used to confirm the formation of Rosocyanine within the particles. Overall, the results demonstrate that TA–PVP nanocarriers successfully stabilize Rosocyanine under physiological conditions, enabling systematic investigation and utilization of its biological properties. Media stability, antioxidant capacity, antibacterial activity, and cytotoxicity of the Rosocyanine‑loaded nanoparticles were evaluated alongside their physicochemical properties. In addition, proof of concept applications in pH sensing, photothermal conversion, and optical data storage were explored, highlighting how stabilization of Rosocyanine opens new opportunities in biomedical and chemical sciences.</p> Graphical abstract <p></p>