  Coulomb and spin blockade spectroscopy investigations have been performed on
an electrostatically defined ``artificial molecule'' connected to spin
polarized leads. The molecule is first effectively reduced to a two-level
system by placing both constituent atoms at a specific location of the level
spectrum. The spin sensitivity of the conductance enables us to identify the
electronic spin-states of the two-level molecule. We find in addition that the
magnetic field induces variations in the tunnel coupling between the two atoms.
The lateral nature of the device is evoked to explain this behavior.
