Studies on the usefulness of rigid-rod molecules to address pertinent questions of biological relevance are summarized. Emphasis is placed on (a) the supramolecular functional plasticity of p-octiphenyl ?-barrels expressed in molecular recognition (adaptable synthetic hosts), molecular translocation (adaptable synthetic ion channels) and molecular transformation (esterases, RNases), (b) molecular recognition of polarized membranes by rigid push-pull rods, as well as (c) the synthetic organic chemistry of rigid-rod molecules.