Recently oligoacenes and oligothiophenes have emerged as important materials for the field of organic semiconductors. It has also been observed that the solid-state packing of such materials is important to achieve efficient charge transfer. In this context, achieving an extended p-p face-to-face orientation of such molecules is desired. Recently, we have published a method for controlling face-to-face p-overlap of oligoacenes and oligothiophenes (semiconductor building blocks, SBBs) based on co-crystallization. Specifically, 2,5-bis(4-pyridylethynyl)thiophene and 9,10-bis(4-pyridylethynyl)anthracene were allowed to co-crystallize with a ditopic hydrogen bond donor molecule, namely a resorcinol derivative, acting as a semiconductor co-crystal former (SCCF). The resulting dimeric assemblies contain a face-to-face orientation of the semiconductor ring systems affording a controlled increase in p-orbital overlap. The crystal structures of the compounds, in the context of enhancing p-orbital overlap will be discussed.