The natural dye extracted from lawsonia inermis seed was successfully used as dye sensitizer for pure and pre dye treated TiO2 nanoparticles synthesized using conventional and modified sol–gel techniques. The PXRD analysis confirms the anatase phase of TiO2 nanoparticles calcined at 250 C. The UV–vis absorption studies confirms the more dye absorbance in pre dye treated TiO2 and FTIR spectra confirms the formation of TiO2 in both sol–gel pro- cesses. The SEM images confirm the improved morphology and re- duced agglomeration due to pre dye treatment. DSSCs were fabricated using conventionally prepared and pre dye treated TiO2 sensitized by lawsone pigment rich natural dye. The light to electron conversion efficiency of conventional and pre dye treated TiO2 based DSSCs are 1.0% and 1.47% respectively. The modified sol–gel process yielding pre dye treated TiO2 nanoparticles showed 47% improvement in efficiency and is a promising methodology in terms of more dye adsorption, less dye aggregation. Therefore, the natural dye extract of lawsonia inermis seed can be used as an effective photo sensitizer and the modified sol–gel synthesis process of producing pre dye treated TiO2 nanoparticles can be adopted for making DSSCs with improved efficiency.