This talk describes complementary strategies to synthetically tailor the excited states of molecular and supramolecular organometallic compounds. We have addressed the long-standing challenge of designing efficient and stable blue-phosphorescent molecules, currently one of most significant technological hurdles in color display technology. Our efforts have resulted in new designs for blue-emitting iridium and platinum complexes, using strongly σ-donating acyclic diaminocarbene supporting ligands installed by unconventional routes relying on the electrophilic reactivity of coordinated isocyanides. Using a different strategy, we have employed nitrogen-containing, π-donating ancillary ligands in the development of new bis-cyclometalated iridium complexes which are efficient red and near-infrared phosphors or potent photoreductants for applications in photoredox catalysis. This talk will also highlight modular strategies to prepare multi-chromophore arrays featuring cyclometalated iridium, providing easy access to new classes of luminescent supramolecular constructs. In addition to providing rich platforms for studying fundamental aspects of excited-state dynamics, some of these compounds function as ratiometric oxygen sensors in hypoxic environments.