A concept that plays an important role in chemistry in general and in molecular spintronics in particular is electronic communication through molecular bridges. An improved understanding of this concept may help to transfer knowledge between different areas of chemistry and nanoscience. We aim at finding the limits of electronic communication as a property of the bridge by comparing and rationalizing trends in exchange spin coupling in diradicals and in conductance in dithiolate-gold junctions which share common sets of molecular bridges.