The present invention provides stock solutions for production of nonlinear-optical materials using a wet coating method. In particular, the invention provides a stock solution containing a nonlinear-optically active organic compound, which is a push-pull .pi.-conjugated compound having a particular chemical structure, having one or more cross-linkable functional groups. In addition, the invention provides a stock solution comprising a nonlinear-optically active organic compound having at least a certain chemical structure and a matrix-forming compound having one or more cross-linkable functional groups. Further, the invention provides a nonlinear-optical material and a nonlinear-optical device, both prepared by using the stock solutions.