It is important, both for basic science and device applications, to investigate the static and dynamic director distribution in a thin nematic liquid crystal (NLC) slab confined between two transparent electrodes. Optical and electrical measurement methods are generally used to determine the director distribution as a function of an electric field. It is to be expected that deuterium NMR spectroscopy combined with simultaneous in situ observation of the light transmittance should give us a good understanding of the director distribution for a thin NLC slab because the former is the sum of the spectra for each position in the slab and the latter by the optical anisotropy averaged over the slab. This combined method is used to investigate the director distribution in a thin NLC slab of 4-pentyl-4'-cyanobiphenyl subject to competing constraints. (c) 2005 Elsevier B.V. All rights reserved.