The synthesis and characterization of a series of mono- and dinuclear ruthenium(II) and osmium(II) polypyridyl complexes based on the heteroditopic bridging ligand PT are reported. This ligand incorporates bidentate phen (1,10-phenanthroline) and terdentate tpy (2,2':6',2''-terpyridine) units directly connected by their 3 and 5 positions, respectively. The dinuclear complexes have been synthesized via a Pd(0) catalyzed cross-coupling reaction between a bromo-substituted Ru-phen complex and a tpy derivative incorporating a boronate ester, followed by Ru(II) or Os(II) complexation. The compounds obtained are fully characterized using spectroscopic and electrochemical measurements. The electrochemical studies do not yield any evidence for interaction between the two metal centers in the dinuclear compounds. Emission studies indicate, however, energy transfer from the phen moiety to the tpy center. For the ruthenium/osmium species, this process is relatively slow, resulting in a dual emission. The emission of the mononuclear ruthenium compound is enhanced by the addition of Zn(II).