  We present a simple and reliable method for making electrical contacts to
small organic molecules with thiol endgroups. Nanometer-scale gaps between
metallic electrodes have been fabricated by passing a large current through a
lithographically-patterned Au-line with appropriate thickness. Under
appropriate conditions, the passage of current breaks the Au-line, creating two
opposite facing electrodes separated by a gap comparable to the length of small
organic molecules. Current-voltage characteristics have been measured both
before and after deposition of short organic molecules. The resistance of
single 1,4-benzenedithiol and 1,4-bezenedimethanedithiol molecules were found
to be 9M$\Omega$ and 26M$\Omega$, respectively. The experimental results
indicate strong electronic copuling to the contacts and are discussed using a
relatively simple model of mesoscopic transport. The use of electrodes formed
on an insulating surface by lithography and electromigration provides a stable
structure suitable for integrated circuit applications.
