The aim is to study how the bandgap can be varied with different functional groups added to the polymer. The calculations are initially compared with the corresponding experimental values for various sulfone compounds.The method is further extended to PEO functionalized with groups like OH, COOH, NH2,NP and(CH3)3Si to study how the bandgap can be engineered by varying the chemistry of the material.The aim is to study how the bandgap can be varied with different functional groups added to the polymer. The calculations are initially compared with the corresponding experimental values for various sulfone compounds.The method is further extended to PEO functionalized with groups like OH, COOH, NH2,NP and(CH3)3Si to study how the bandgap can be engineered by varying the chemistry of the material.