Fundamental to the field of organic electronics is the understanding that structure begets function. For conjugated polymers, monomer structure determines overall energy levels while also influencing interchain interactions. These interchain interactions induce aggregation and creates higher order morphology, greatly influencing the ultimate performance of electronic devices. Understanding the interplay of morphological changes with device efficiency is imperative to improving the performance of organic electronics with minor differences in molecular structure, linear versus branched side-chains, carbon versus silicon bridgehead atoms or hydrogen versus fluorine substitution, having dramatic effects on the energetics, aggregation, morphology, and, ultimately, performance of these materials. This report highlights the power of minor structural changes in conjugated polymers and the associated design rules for the preparation of next generation electronic materials.