This thesis concerns the rational design of supramolecular metal-complexes and assemblies through combination of tripodal ligands and geometrically directing metallotectons. The aim of this work is to impart functionality into the resultant complexes, with a view towards applications exploiting the inherent luminescent emission of the systems. The metallotectons discussed in this thesis all derive from low-spin d6 metal centres, with incorporation of ancillary ligands designed to retain and modulate the resultant luminescent emission leading to high-fidelity control over the emissive outcome. Three families of complexes were synthesised; incorporating Re(I), Ru(II) and Ir(III) in combination with supporting ancillary ligands and a pair of bi-dentate bipyridine-appended cavitand ligands. The photophysical properties of these systems were investigated and rationalised with respect to both the structural motif of the cavitand ligands and the structure of the metallotecton. The Ir(III) family of complexes was expanded upon to give rise to both tri-metallic and mono-metallic systems, retaining vacant coordination sites. These vacant sites were subsequently exploited in the formation of heterometallic and heteronuclear assemblies employing secondary Ir(III) metallotectons and Ru(II) metallotectons respectively. This novel, modular approach allows for high-fidelity control over the emission properties and gives rise to a ‘function-driven’ route towards metallo-supramolecular design. The self-assembly of the aforementioned d6-metallotectons in combination with mono-dentate cavitand ligands was also investigated, leading to the formation of the first example of an ambi-dentate heteroleptic Re(I) metallocryptophane and a Ru(II)-cornered metallo-cube. A family of novel luminescent Ir(III) metallocryptophanes were also formed, one of which was crystallographically elucidated. The emission colour was modulated between blue-green and intense yellow luminescence depending on the nature of the ligand, and with large internal cavities these cages possess potential in host-guest chemistry.