Abstract
After reviewing some of the recent progress achieved in electroconvection of planarly oriented nematics we present a weakly nonlinear theory for the homeotropically oriented case for materials with negative dielectric anisotropy. Then one first has a Freédericksz transition that spontaneously breaks the isotropy in the plane of the convection layer and subsequently the convective instability. As a result the Goldstone mode resulting from the broken isotropy couples to the amplitude of the patterning mode. The equations exhibit new types of spatio-temporal chaos at onset.