In this study, GPTMS-functionalized bio-silica reinforced Schiff base polybenzoxazine hybrid composites, based on a triazine-cored benzoxazine structure, were developed for high-performance thermal, flame retardant, and corrosion-resistant applications. Benzoxazine monomers were synthesized via Mannich condensation using triazine-based trisphenol (CN-IM) and four amines: aniline (a), furfuryl amine (fa), lauryl amine (la), and stearylamine (sa), with structural confirmation by FT-IR and NMR analyses. Among these, CN-IM-sa was selectively used for hybrid composite development due to its comparatively lower thermal stability, along with its inherent good corrosion resistance and superior hydrophobicity, aiming to enhance its protective performance through bio-silica reinforcement. Catalyst-assisted curing of CN-IM-sa reduced the curing temperature to 188 °C. The poly(CN-IM-sa)/bio-silica hybrid composite exhibited significant improvements, including a water contact angle of 130°, corrosion inhibition efficiency of 99.3 %, and improved thermal stability confirmed by high residual char. These results highlight the potential of CN-IM-sa/bio-silica hybrids as multifunctional coatings for corrosion protection in aggressive environments.