[Figure not available: see fulltext.] The possibility of intramolecular nucleophilic aromatic substitution of hydrogen in the series of 5-[2-(het)aryl-1-benzothiophen-3-yl]-pyrimidines was explored. A convenient method for the synthesis of [1]benzothieno-[3,2-f]thieno[2,3-h]quinazoline and [1]benzothieno-[3,2-f]thieno[3,2-h]quinazoline based on the developed S_N ^H protocol was proposed. The energy parameters (width of the band gap, the energy of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbitals (LUMO)) of benzothieno[3,2-f]-thieno[2,3-h]quinazoline synthesized for the first time were determined based on the data of the absorption spectra and cyclic voltammetry.