The design of polymer semiconductors possessing effective - intermolecular interactions coupled with good solution processability remains a challenge. Structure-property relationships associated with side chain structure, - intermolecular interactions, polymer solubility, and charge carrier transport are reported for a donor-acceptor(1)-donor-acceptor(2) polymer: 5-Decylheptadecyl (5-DH), 2-tetradecyl (2-DT), and linear n-octadecyl (OD) chains are substituted onto a polymer backbone consisting of terthiophene units (T) between two different electron acceptors, benzothiadiazole (B), and diketopyrrolopyrrole (D), pTBTD, to afford pTBTD-5DH, pTBTD-2DT, and pTBTD-OD, respectively. In the 5-DH side chain, the branching position is remote from the polymer backbone, whereas it is proximal in 2-DT. This study demonstrates that incorporation of branched side chains where the branching position is remote from the polymer backbone merges the advantages of improved solubility from branched units with effective - intermolecular interactions normally associated with linear chains on conjugated polymers. pTBTD-5DH exhibits superior qualities with respect to the degree of polymerization, solution processability, - interchain stacking, and charge carrier transport relative to the other analogs. pTBTD-5DH exhibits a field-effect hole mobility of up to 2.95 cm2 V-1 s-1, a factor of 3-7 times that achieved with pBDT6-DT and pBDT6-OD.