Density functional theory study of electronic structure and spectra of tetraoxa[8]circulenes

► Spectra of tetraoxa[8]circulenes are explained on the ground of TD DFT calculations. ► The nature and intensity of observed absorption and fluorescence bands are explained. ► Emission of OLED devices using these materials are modified comparing to the solvents. ► All features are connected with the excited states symmetry of the studied molecules.