2,5-Bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (TTP) derivatives having four long alkylthio chains

π-Electron donors having four long alkylthio chains, TTCn-TTP (2,5-bis[4,5-bis(alkylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene; n=2–5; ) have been synthesized. Crystals consisting of the neutral donors show moderately low resistivities (6×103–6×107 Ω cm). Origins of the low resistivities are investigated by X-ray analyses; TTC3-TTP () displays so-called θ-type donor arrangement in contrast to TTC4-TTP () with uniform-stacked one, both of which indicate fastener effect.