We design a series of expanded porphyrins which are incorporated of dithienothiophene (DTT), 2,2′-bithiophene, inverted thiophene ring or selenophene ring and substituted of the pyrrole NH groups by S and Se heteroatoms. The molecule with 2,2′-bithiophene is more stable than the molecule with DTT. The expanded porphyrins with a thiophene or selenophene ring are more stable than the expanded porphyrins with an inverted thiophene or inverted selenophene ring. 6 shows special features due to its increased HOMO-LUMO gap, planar geometry, and stre...
