The theoretical study on the ground state geometries and electronic properties of new conjugated compounds using benzothiadiazole and pyrole as substrates was carried out using density functional theory (DFT) method at B3LYP level with 6-31G* basis set. The dihedral angle, bond length, electronic and UV-Visible absorption properties were determined. The coupling (of the donor and acceptor) and substituent effects on the geometry and electronic properties of these substrates were discussed.The results show that the geometries of the materials were significantly affected by the substituents. The substitution of the pyrrole ring with pyrrolium oxide destabilizes the HOMO, LUMO levels with a decrease in a band gap and results in a red shifting in the absorption spectrum. The theoretical results suggest that both the donor strength and the stable geometry contribute significantly to the electronic properties of alternating donor–acceptor conjugated copolymers. These electronic properties compared favourably with conjugated copolymers that had been used in optoelectroniv devices. Hence, these copolymers could have potential applications in transparent conductors, or photovoltaic devices.