9-(Dicyano­methyl­idene)fluorene–tetra­thia­fulvalene (1/1)

The title compound, C(16)H(8)N(2)·C(6)H(4)S(4), crystallizes with the fluorene derivative placed in a general position and two half tetra­thia­fulvalene (TTF) mol­ecules, each completed to a whole mol­ecule through an inversion center. The fluorene ring system is virtually planar (r.m.s. deviation from the mean plane = 0.027 Å) and the dicyano group is twisted from the fluorene plane by only 3.85 (12)°. The TTF mol­ecules are also planar, and their central C=C bond lengths [1.351 (8) and 1.324 (7) Å] compare well with the same bond length in neutral TTF (ca 1.35 Å). These features indicate that no charge transfer occurs between mol­ecules in the crystal; the compound should thus be considered a cocrystal rather than an organic complex. This is confirmed by the crystal structure, in which no significant stacking inter­actions are observed between mol­ecules.