However, DFT simulations propose strong orbital coupling between polymer and dopant, which should favour partial charge transfer complex (CTC) formation instead of the experimentally observed IP formation. This has been one of the long-standing debates in F 4 TCNQ doped P3HT system. Now the general consensus has shifted to the opposite direction-that the F 4 TCNQ anion sits in the lamellar stacking region between the side-chains that would be conducive to IP formation. Recent observations suggest that molecular doping in this system might be more complex. Jacobs et al. reported a P3HT/F 4 TCNQ crystalline polymorph, which gives rise to CTC formation, but interestingly can be converted back to the standard IP polymorph by solvent exposure. This result apart from highlighting the role of intermolecular interactions and onset of crystalline structures, also shows the importance of solvent in attaining the IP polymorph with higher electrical conductivity. In fact, Müller et al. have shown how interactions in solvent might pre-define doping efficiency of F 4 TCNQ doped P3HT films. Thus, it is essential to study the electronic interactions in precursor solution mixtures, which may seed the polymer-dopant interactions in spin-casted films.