( Z )‐2‐Phenyl‐3‐(2,2′:5′,2′′‐terthiophen‐3′‐yl)acrylonitrile

In the crystal structure of the title compound, C 21 H 13 NS 3 , one of the terminal thiophene rings is disordered in approximately a 3:1 ratio of components, and the disorder is of the flip type. The terthiophene units are far from coplanarity, in contrast to terthiophene itself. The conformation might be described, for the unit of greater occupancy, as quasi‐ cis [the S—C—C—S torsion angle is 41.1 (5)°] quasi‐ trans [the S—C—C—S torsion angle is −140.1 (4)°], and for the less‐occupied part as quasi‐ cis –quasi‐ cis [35.7 (6)°]. The dihedral angle between the terminal ring planes is as high as 71.7 (2)°. The central C—C=C—C group is almost planar [maximum deviation of 0.027 (3) Å] and it is approximately equally twisted with respect to both the central thiophene and the phenyl ring planes [26.5 (4) and 23.5 (7)°, respectively]. The crystal packing is determined by van der Waals interactions, and some weak C—H...N and C—H...π relatively short directional contacts.