Secondary aromatic amines are compounds containing an amine group attached to an aromatic ring, usually in the secondary (R2N-) configuration. They are known for their good hole transport properties, making them suitable for use as p-type semiconductors. Secondary aromatic amines can undergo oxidative doping, which helps inject holes into the semiconductor layer, enhancing its conductivity. Their ability to form stable charge transfer complexes with electron accepting moieties facilitates their use in donor-acceptor copolymers for solar cells. Secondary aromatic amines have found application in OLEDs, where they serve as hole transport layers or emitters, and in OFETs for improved charge transport.