Controlling the Growth of Molecular Crystal Aggregates with Distinct Linear and Nonlinear Optical Properties

Two novel donor–acceptor
molecules, 2,7-diphenylbenzo­[1,2-b:4,3-b′]­difuran-4,5-dicarbonitrile and 2,7-bis­(4-methoxyphenyl)­benzo­[1,2-b:4,3-b′]­difuran-4,5-dicarbonitrile
containing cyano group as the electron acceptor, were synthesized.
Their single-crystal structures, molecular packing, and self-assembly
behaviors were also investigated. By simple solvent evaporation techniques,
these compounds self-assemble into various low-dimensional microstructures
that demonstrate distinctive nonlinear optical properties depending
on the orientations of their transition dipoles. This study highlights
the importance of the transition dipole moment in the construction
of low-dimensional molecular materials with highly efficient nonlinear
optical properties.