A versatile convergent synthesis route to side chain pi-extended, highly regioregular polythiophenes is presented. The implementation of beta-conjugated alkyl thiophene branches in linear polythiophenes is used as synthetical tool for energy level engineering, with branched alkyl chains being introduced for solubility reasons. While the length of the branched alkyl side chains does not influence the functional properties, the aggregation behavior in solution does vary from highly aggregated to fully dissolved at room temperature. Temperature-dependent UV-vis spectroscopy highlights the differences in the aggregation behavior in solution and thin films. The aggregation behavior in solid state is further studied using DSC temperature-dependent Raman spectroscopy and temperature-dependent XRD. Finally, controlled crystallization conditions via solvent vapor annealing are applied to allow the formation of spherulite-like structures which reveal a face-on orientation of the polymer backbone with respect to the substrate.