Titanium dioxide nanoparticles have been synthesized by a novel modified sol-gel for the fabrication of natural dye sensitized solar cells. The natural photo sensitizer extracted from Cordia sebestena flower was mixed with the precursor solution. The flower dye has put the effort of a surfactant which has resulted colourized TiO2 instead of white TiO2. Whencompared to the conventional sol-gel method, this modified process has enhanced the properties of TiO2 like, morphology, uniformity in dye absorption. It has reduced the agglomeration of TiO2 and dye aggregation significantly. The optimized molecular geometry of sebestenoid D, the major pigment of Cordia sebestena and HOMO-LUMO plot are found using density functional theory. The TiO2 nanoparticles were subjected to structural, optical, spectral and morphological studies which showed improved properties in modified sol-gel process. Ecofriendly and low-cost natural dye sensitized solar cells (DSSC) were fabricated using conventional and pre-dye treated TiO2 sensitized by Cordia sebestena flower extract. The I-V studies showed the solar light photon to electron conversion efficiencies of 0.87 and 1.28 % for sol-gel and modified sol-gel methods, respectively. There has been an enhancement in efficiency by 47 % in modified sol-gel method which is very much promising in terms of efficiency for natural dye sensitized solar cells.