Hybrid devices built from organic and inorganic moieties are being actively researched as replacements for inorganic electronics, thermoelectrics, and photovoltaics. However, energy transport and conversion, at the organic-inorganic interface is not well understood. One approach to study this interface is to look at the smallest hybrid building block - the heterojunction of a single organic molecule with inorganic contacts. We present a review of this work, focused on fundamental transport properties of metal-molecule-metal junctions that are related to thermoelectric energy conversion, i.e., electronic conductance, thermopower, and thermal conductance. We describe the motives, strategies, and future directions for considering heterojunctions as building blocks for thermoelectric materials. (C) 2010 Elsevier B.V. All rights reserved.