Conjugated polythiophenes (PTs) have emerged as a promising class of material in organic solar cells. The device performance depends on the inherently-linked optoelectronic properties and nanoscale morphology of the PT. Hence, there is substantial interest in developing novel approaches to control the morphology of PTs. In this study we will investigate if the co-assembly of cationic, diblock PTs with anionic surfactants can be used to form PT-surfactant complexes with targeted organisation. Using small-angle neutron scattering (SANS) we intend to observe the global and internal structural organisation of the PT-surfactant aggregates formed. Optical spectroscopy will also be used to correlate the aggregate structure with the photophysical properties.