This proposal aims at the development of low valent and low coordinated arsenic and phosphorus compounds and their application in organic electronics. The electronic properties of known building blocks for organic electronics are greatly influenced by the replacement of a carbon fragment in the conjugated backbone with an isolobal pnictogen (group 15 element, e.g. P-R or As-R) fragment. By the heteroelement incorporation we aim to achieve a stabilization of the LUMO levels, without affecting the energies of the occupied orbitals. This leads to materials that are good electron acceptors and tned to have high stabilization of (bi-) radical states. Within this project we will frurther develop the chemistry of Truxene based electron acceptor materials as well as create a detailed understanding on the interplay of singlet ground and biradicaloid (twisted) contributions in phosphorus heteroquinoidal molecules.