A small molecular thiophene compound consisting of a plurality of thiophene units, each thiophene unit being represented by structure (A) ##STR00001## wherein each thiophene unit is bonded at either or both of the second ring position and the fifth ring position, wherein m is 0, 1, or 2, wherein each thiophene unit is the same or different from each other in terms of substituent number, substituent identity, and substituent position, wherein each R.sub.1 is independently selected from the group consisting of: (a) a hydrocarbon group, (b) a heteroatom containing group, and (c) a halogen, wherein there is at least one thiophene unit where R.sub.1 is present at the third ring position or the fourth ring position, or at both the third ring position and the fourth ring position, wherein for any two adjacent thiophene units as represented by structure (A1): ##STR00002## there is excluded the simultaneous presence of the same or different R.sub.1 at the 3-position of one thiophene unit and at the 3'-position of the other thiophene unit wherein R.sub.1 is not part of a cyclic ring structure fused to the thiophene unit.