To achieve flow-induced alignment, we developed microfluidic devices to access very high shear (~10 6 s -1 ) and extensional (~10 5 s -1 ) strain rates that have not been accessed before in prior microfluidic flow birefringence studies. Such high strain rates are necessitated by the rapid relaxation of conjugated polymer aggregates in solution. Using microfluidics in combination with in situ retardance measurements, we are able to directly quantify the dependence of alignment on varying flow conditions. Furthermore, to study the effect of the solution state on flow-induced alignment, we varied the concentration and also tuned the solution aggregation by adding a poor, polar solvent resulting in longer and more rigid fibril aggregates as determined by freeze dried imaging and small angle X-ray scattering (SAXS). Our study reveals the complex interplay between fluid flow and the conjugated polymer aggregation and its effect on flowinduced alignment, finding that simply increasing flow strength or aggregation does not necessarily lead to improved alignment. The results here can be used to inform design rules for solution processing in order to leverage potential synergies and improve film morphology in an efficient manner.