In this proposal we will mostly study the electronic structures of open-shell (mostly biradical, radical cationic and radical anionic) sepcies that are based on extended conjugated frameworks as well as main group elements that are structurally embedded in those. The different main group "dopants" (e.g. unsaturated boron, phopshorous nitrogen, arsenic) will greatly alter the electronic structure and hence will influence the radical properties. Du to the possible multi-reference character post HF methods will be used extensively to explore and accurately descrie the electronic situations. Especially, for the larger systems a combination of various approaches (DFT, MD) will be used to treat these molecules as ensembles (roatmers and conformers) to accurately describe the bulk properties. The project is based on the granted VR project (2021-03658_VR) dealing with hetero-quinoidal main compounds for the acticvation of small molecules and E-H bonds. However, this theoretical study will go beyond that exploreing hitherto unknown chemical motifs, especially towards contorted / helical/ twisted polyaromtic hydrocarbons.