In summary, we report the solution state of PII-2T and other D-A conjugated polymers consists of fibril aggregates in addition to a population of dispersed polymers. We showed through using various SAXS scattering profiles at different MW and solvents that the solution state conformation and aggregate structure can be inferred through careful analysis. We presented two models to explain the small angle scattering of D-A conjugated polymers which exhibit complex pre-aggregated behavior. The 2SFC model was generally applicable and was well suited to fitting the scattering profiles, yielding parameters in good agreement with freezedried imaging results. Likewise, the FA model also yielded parameters in good agreement with imaging results. Using the FA model we were able to demonstrate that the origin of the structure factor peak was due to side chain stacking from polymers within the fibril aggregates. To support our picture of the solution state and the applicability of our models, we carried out direct imaging