The present work reports the synthesis and characterization of nanostructured poly (o-toluidine) (POT) reinforced epoxy-siloxane (ES) composite resins. The structural elucidation was carried out using FT-IR and UV-visible spectrometry. The FT-IR analysis confirmed the interaction between NH group of the POT and the OH group of ES via strong hydrogen bonding. The UV-visible spectra of POT/ES composites revealed a blue shift of 100 nm in the polaronic transition peak observed at 600 nm in pristine POT, which was attributed to the restriction in the delocalization of polarons in the POT chains due to electrostatic interaction via hydrogen bonding. The nanosize of POT and its dispersion in the ES matrix was confirmed by X-ray diffraction (XRD) and transmission electron microscopy studies. The particle size was found from 15-35 nm. The morphological studies confirmed the formation of a nanocomposite where POT appeared to act as reinforcing agent in the ES matrix. XRD showed the semi-crystalline nature of POT/ES nanocomposites. The conductivities of POT and its nanocomposites were 10(-3)-10(-4) S/cm at 30 A degrees C. The thermal stability increased with an increase in the loading of POT in ES. The nanocomposites revealed good physico-chemical and physico-mechanical characteristics, which suggests their potential application as corrosion protective coatings.