Electro-oxidation of tetramethyltetrathiafulvalene (TMTTF) in the presence of the chiral anion (1 S )-camphor-10-sulfonate (S-camphSO 3 − ) in tetrahydrofuran/water medium afforded a 1/1 salt formulated as TMTTF·S-camphSO 3 ·2H 2 O or 2-(4,5-dimethyl-1,3-dithiol-2-ylidene)-4,5-dimethyl-1,3-dithiole radical ion (1+) (1 S )-7,7-dimethyl-2-oxobicyclo2.2.1heptan-1-ylmethanesulfonate dihydrate, C 10 H 12 S 4 + ·C 10 H 15 O 4 S − ·2H 2 O. In this salt, two independent TMTTF units are present but, in both cases, the observed bond lengths and especially the central C=C distance 1.392 (6) and 1.378 (6) Å are in agreement with a complete oxidation of TMTTF which is thus present as TMTTF . + radical cations. These cations form one-dimensional stacks in which they are associated two by two, forming dimers with short 3.472 (1) to 3.554 (2) Å S...S contacts. The two S-camphSO 3 anions present also form stacks and are connected with each other via the water molecules with many O—H...O hydrogen bonds ranging from 1.86 (3) to 2.15 (4) Å; the O—H...O hydrogen-bonding network can be described as being constituted of C 2 2 (6) chains bearing R 3 3 (11) lateral rings. On the other hand, the columns of cations and anions are connected through C—H...O hydrogen bonds, forming a system expanding in three directions; finally, the result is a three-dimensional network of O—H...O and C—H...O hydrogen bonds.