Described is the synthesis and the single-crystal structure of an all-
trans dicyano-substituted five-ring PPV oligomer having two 12-octylox
y side chains attached onto the central phenyl ring. The crystal densi
ty (D-calc = 1.210 g cm(-3)) appears to be almost 10% higher than that
of the crystalline phase of the analogue without cyano substituents.
This indicates the presence of considerable packing forces, which is r
eflected in a remarkable ''wavelike'' deformation from planarity of th
e conjugated backbone and the stretching of the n-octyloxy side chains
along the backbone. We attribute this dense packing to a large Coulom
b interaction between neighbor molecules as a result of cyano substitu
tion. Our results suggest that such intermolecular interactions play a
n important role with respect to the molecular geometry and packing in
the solid state of cyano-substituted PPV-based materials.