Abstract: A nonlinear optical material which is characterized as having a relatively high macroscopic dipole moment achieved through the generally parallel packing of dipolar molecules in a relative orientation to reinforce their dipole moments. The nonlinear optical material may be a crystalline azine or imine bridged di-arene in which the arenyl groups, which can be the same or different, are substituted with an electron donor group on the first arenyl group Ar1 and A is an electron acceptor group which is substituted on the second arenyl group Ar2. B is an azine or imine bridge which extends between and interconnects the first and second arenyl groups. The nonlinear optical material has a dipole alignment factor of at least 0.1, more preferably, at least 0.5.