The siloxane based flexible cardanol benzoxazine was synthesised using cardanol, 1,3-bis(aminopropyl) tetramethyldisiloxane and p-formaldehyde through solvent free method and was characterised by different analytical techniques. A new fangled nanocomposites of amine functionalised rice husk ash silica reinforced siloxane based flexible cardanol benzoxazine were developed and their molecular structure, molecular weight, morphology, cure behaviour, thermal stability, dielectric character and corrosion resistant behaviour were carried out by appropriate test methods. Data obtained from differential calorimetric analysis and experimental cure process infer that the siloxane based cardanol benzoxazine cures at 110 °C, which is significantly lower temperature when compared to that of conventional benzoxazines cure between 220 and 280 °C. Results from dielectric and corrosion resistant studies indicate that these renewable hybrid composite materials can be conveniently used in the form of adhesives, encapsulants, sealants and potting compounds for high performance, low k materials in microelectronics and as coatings to protect steel surfaces from corrosion and microbial deterioration.