SCORS will deliver a paradigm change for organic semiconductor science and technology by exploring and developing the electronic and optical properties of radical (spin ½)-based organic semiconductors (ROSCs). The proposer has recently discovered these can show very efficient photoluminescence and can support efficient organic light emitting diodes (OLED) operation within the spin doublet manifold. SCORS will comprise five key themes:<br/>1) Develop and synthesize new structures for ROSCs to control emission colour and efficiency, explore fundamental mechanisms for high luminescence yield, and search for optical gain. Targets: efficient red and IR emitters out to 1µm; optically driven cw-lasing.<br/>2) Establish the use of doublet excited states for their spin-allowed interconversion with both singlet and triplet excitations in OLED structures. Target: New OLED designs that use fast luminescence ROSCs materials in OLEDs with conventional singlet/triplet semiconductors such as TADFs, with high efficiencies (EQE>25% at high brightness (1000 cd/m2). <br/>3) Develop IR-emitting ROSCs that energy-match triplet excitons formed in singlet exciton fission systems. Targets: doublet systems as optical emitters for singlet fission based down-conversion to improve photovoltaic efficiency. Search for direct singlet to triplet-doublet pair fission.<br/>4) Use of ROSCs in Organic Photovoltaics (OPVs) to provide light absorbers that are designed to have no lower-energy (and therefore quenching) excitations. New materials designs to delocalize electron and hole wavefunctions will be developed. Target: a paradigm shift for OPVs - high luminescence efficiencies enabling high open circuit voltage, with non-radiative recombination voltage loss < 100 meV.<br/>5) Explore the control the ground state spin polarisation in ROSCs. Targets: realisation of new spintronic devices, using spin injection and new detection schemes.