A solution blending process for preparation of polymer nanocomposites composed of cationic polyfluorene (PF) and dimethyl sulfoxide (DMSO) -intercalated kaolinite (Ka) clay has been taken to evaluate the effect of Ka nanostructure on the nanocomposite structures, morphology, and properties. Composites containing 2, 5, 7.5, and 10 wt % clay have been characterized with the help of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, photoluminescence studies, etc. Additionally, the keto defect, inhibition of interchain interaction; and photostability of PF in the nanocomposites have been explored. The XRD and HRTEM studies show the exfoliation of Ka layers at lower content in composites. Intercalation of PF chains into the Ka interlayer space occurs at relatively higher clay content. Nanocomposites exhibit higher thermal stability than pristine PF due to lamination of PF into clay nanogallery through the interchange of DMSO by cationic polyfluorene. The presence of an Si-O-Si stretching band in the composites supports the formation of nanocomposites of PF with Ka. The movement of absorption maxima to higher wavelength indicates the increase of overall conjugation length of PF chains in the nanocomposites. Upon formation of nanocomposite with Ka, the keto defect sites of PF are significantly reduced. This can be attributed to the lamination of single PP chains by Ka interlayer gallery that act as a barrier to oxygen and inhibit the exciton diffusion. Current-voltage characteristics of nanocomposite films have also shown good switching behavior with low forward junction potential.