  We develop scenarios for orientational ordering of an in-plane system of
small flat octupolar molecules at the low-concentration limit, aiming towards
nonlinear-optical (NLO) applications at room temperatures. The octupoles
interact with external electric poling fields and intermolecular interactions
are neglected. Simple statistical-mechanics models are used to analyze the
orientational order in the very weak poling limit, sufficient for retrieving
the NLO signals owing to the high sensitivity of NLO detectors and measurement
chains. Two scenarios are discussed. Firstly, the octupolar poling field is
imparted by a system of point charges; the setup is subject to cell-related
constraints imposed by mechanical strength and dielectric breakdown limit. The
very weak octupolar order of benchmarking TATB molecules is shown to emerge at
Helium temperatures. The second scenario addresses the dipoling of octupolar
molecules with a small admixture of electric dipolar component. It requires a
strong field regime to become effective at Nitrogen temperature range. An
estimation of the nonlinear susceptibility coefficient matrix for both
scenarios is done in the high-temperature (weak interaction) limit formalism.
We argue that moderate modifications of the system like, e.g., an increase of
the size of the octupole, accompanied by dipole-assisted octupoling, can
increase the poling temperature above Nitrogen temperatures.
