Organic semiconductors with tunable optoelectronic properties are of great interest for applications in flexible electronic devices,such as organic field-effect transistors(OFET)and organic photovoltaics(OPVs).The development of electroactive units that satisfy bandgap engineering,high absorptivity,and strong intermolecular interactions is amongst the most fundamental tasks for material property optimization.In this talk I will describe the design and synthesis of new electron donors and acceptors,i.e.thienoazacoronene(TAC)1 and bay-annulated indigo(BAI)2 derivatives,and their incorporation in conjugated polymers.The combination of molecular level understanding of material composition and control of thin film ordering offers great opportunity for the development of novel high performance electronic materials.