A series of tetraalkylthio substituted tetrathiafulvalenes (TTCn-TTF) was prepared. The syntheses, molecular and crystal structures, and physical properties of TTCn-TTF reveal marked differences from those of BEDT-TTF. The conformational change of TTC1-TTF molecule on the formation of chargetransfercomplexes and the mode of the S…S contacts are described in connection with those of BEDT-TTF compounds