In PM7, the highly fused benzodithiophenedione (BDD) based acceptor moiety is incorporated, while for PM7 D1 and D2 polymers, this BDD based moiety is replaced with an ester functionalized terthiophene moiety which leads to a wider optical bandgap. The difference between the molecular structures of PM7 D1 and D2 is the location of ester group substitution, i.e., in PM7 D1 the two ester groups are located on the first and third thiophene units while in PM7 D2 they are both located on the central thiophene. Recently, Jones et al. showed that this structural modification reduced the required synthetic steps while still maintaining the device performance. The authors have achieved the optimal device performance of 11.6%, 12.1%, and 9.9% respectively for spin coated PM7, PM7 D1, and PM7 D2 when using ITIC-4F as the small molecule acceptor. Interestingly, the authors reported that this structural modification led to a more blue-shifted featureless UV-Vis absorption in both PM7 D1 and D2 solutions as compared to PM7 solution suggesting that the solution-state aggregation could be different. In this work, we will study the solution-state aggregation of these polymers in detail and investigate how different polymer aggregates impact the solid-state morphology and device properties of OSCs.