One of the challenging goals of molecular electronics is to understand and master electronic devices at the single-molecule level.Based on recent progress employing three terminal solid-state devices [1-3] it is possible to interrogate a single molecule in a metal gap in great detail.The talk will focus on new insight into the physics and chemistry of such molecules in particular the influence of metal electrodes on the molecular energy spectrum [1], controlling molecular spin [2] and progress towards chemical preparation of single molecule devices in which the molecule/metal interface can be controlled with atomic precision [3].