Organic semiconductors consisting of conjugated chromophores wherein one or more hydrogen atoms are deuterated are disclosed. Methods of preparing such organic semiconductors are described. The organic semiconducting compounds exhibit remarkably high luminescence and good thermal stability. Applications of these materials for optoelectronic devices, such as light-emitting devices and photodiodes, with enhanced performance and lifetime are disclosed. The disclosed materials can be used as emissive layer, charge-transporting layer, or energy transfer (i.e. phosphorescence dopant) material in organic light-emitting devices.