Partially and fully fluorinated alkyl substituted thienothiophene monomers (and polymers thereof) wherein the monomers are represented by the formula: ##STR00001## wherein R is a partially or fully fluorinated primary, secondary or tertiary alkyl having from 1 to 8 carbon atoms; and X and X' are independently selected from the group consisting of H, F, Cl, Br, I, MgCl, ##STR00002## --COR'', --C.ident.CH, and a polymerizable cyclic pi-conjugated carbon-ring structure optionally comprising S, N or O heteroatoms; wherein R' is a primary, secondary or tertiary alkyl having from 1 to 6 carbon atoms, and R'' is H or a primary, or tertiary alkyl having from 1 to 6 carbon atoms.