The projected fossil fuel deposits depletion by near future and detrimental effects of petroleum products on environment has led to the development of volatile organic compound (VOC) free low molecular weight sustainable polymers, with promising applications in field of inks, adhesives, paints, and coatings. In view of this, present study reports synthesis, characterization, and anticorrosive performance of SMG-PU and modified SMG-PU through in situ formed silica networks (SMG-PU-TEOS) OIH polymer nanocomposite coatings on CS. The size of similar to 30 nm silica nanonetworks were formed within SMG-PU on addition of TEOS, inducing thermal stability, hydrophobic, improved physicomechanical and corrosion resistant properties to polymer nanocomposite coatings. The corrosion protective performance of these coatings in 5% NaCl (salt mist test), 3.5% NaCl, and 3.5% HCl solutions revealed very lower I-corr, values (3.8891 x 10(-10) A cm(-2) and 6.8756 X 10(-9) A cm(-2)) as compared to SMG-PU (1.8159 X 10(-8) A cm(-2) and 9.1396 X 10(-7) A cm(-2)), bare CS (8.9131 X 10(-8) A cm(-2) and 8.1731 x 10(-4) A cm(-2)), and other such reported systems.