Currently, the research in organic semiconductor is heading towards the blends and multilayered structures. In these blends and multilayered systems, the photogenerated carriers can hop from one molecule to another depending on the band alignment and can create an intermediate charge transfer exciton which will increase the probability of charge separation. The optical properties of the blends or heterostructure materials will be different form the pristine material. Which enables us to study the underlying carrier mechanism in the blends and multilayered systems. Apart from optical properties, we can explore the effect of electric field on the materials, nature of excitons and the relaxation mechanism from the spectroscopic techniques. In this talk, I will be discussing about electroabsorption and pump-probe spectroscopy techniques which will be used to explore the carrier dynamics in the pentacene and P3HT systems and their blends.