The development of metal complexes, especially gold, has been greatly influenced by the discovery of their properties, which play a pivotal role in diverse fields, such as organic synthesis, materials science, and medicine. One crucial aspect of this progress is the design of strong donor ligands, which has proven instrumental in stabilizing and enhancing the properties of the complexes. These ligands possess a unique combination of electronic and steric characteristics that can be readily modulated, a key factor in the stabilization and enhancement of gold complexes with intriguing properties. The potential applications of luminescent compounds extend to a wide range of areas, including sensors, OLEDs, photocatalysis, and medicine, contributing to the increasing research interest in these compounds. In this context, we will explore the synthesis of metal complexes with great versatility, employing ligands with distinct donor centers to fine-tune their fluorescence or phosphorescence nature, quantum yield and emission energy across a significant portion of the visible spectrum. Furthermore, when considering gold complexes with biological relevance, the introduction of an organic or organometallic chromophore group can result in luminescent complexes. These luminescent complexes may facilitate the visualization of their localization within cells, providing essential information about their mechanism of action. This makes them valuable as theranostic agents or potential photosensitizers in photodynamic therapy.