In this contribution we explore the use of real time spectroscopic probes to gain useful insights into the kinetics of semiconductor polymer chains during thin film formation and upon post-deposition annealing treatments. In-situ ellipsometry is employed to monitor the deposition of thin films of the workhorse material system for organic photovoltaics (soluble derivative fullerene blended with poly(3-hexylthiophene)), when processed from solution using an analogous dip coating deposition method. This allows for detailed time investigation of the dynamics of film formation. Moreover, we applied spectroscopic photometry to study the in-situ crystallization and diffusion of polymer chains during post-deposition solvent annealing. (C) 2011 Elsevier B.V. All rights reserved.