The synthesis and electrochemical properties are described for a tetrathiafulvalene derivative with -S(CH2CH2O)(3)CH3 oligomers attached at each of its four corners (TTF[E(3)M](4)). This material is a molecular melt at room temperature and will dissolve LiClO4 as a polymer electrolyte. Its radical cation salt, {TTF[E(3)M](+)(4)}{CF3SO3-}, is also a room temperature melt in which LiClO4 is soluble. Microelectrode voltammetry in LiClO4 + TTF[E(3)M(4)] and in {TTF[E(3)M](+)(4)}{CF3SO3-} shows that the self-diffusivities of these TTF derivatives in their melts are quite small and have room temperature values ranging from 8 X 10(-9) to 5 X 10(-12) cm(2) s(-1) depending on the LiClO4 content. The experimental diffusion coefficients derived from voltammetric waves for the TTF[E(3)M](0/+)(4) couple are larger than those for the TTF[E(3)M](+/2+)(4) couple by factors ranging from 2.5 to 13, a difference not understandable by migration effects alone. Consideration of coupling of homogeneous TTF[E(3)M](0/+)(4) electron self-exchange to diffusion during TTF[E(3)M](+)(4) reduction or TTF[E(3)M](4) oxidation leads to estimation of k(EX,1/0) values in the 10(5) M(-1) s(-1) range and which increase with temperature and decrease with the addition of LiClO4 electrolyte.