The scope and limitations of the synthesis of unsymmetrically substituted TTF derivatives via the “phosphonate way” was investigated using as precursors 1, 3-dithiol-2-yl-phosphonates and 1, 3-dithiol-2-yliden iminium salts with various substitutents on the dithiole cycles. Except for the un-or monosubstituted phosphonates, the one-pot procedure proves to be general and affords in all cases a significant improvement in the overall yields in TTF ...