This dissertation includes exploring two scientific challenges, where both water oxidation catalysis and NH addition to alkynes will benefit greatly from the rational design of ligands. Chapter 1: The long-term goal for scientists is to use sunlight for the energy to split water. The main target of our research is the oxidation half reaction. Water oxidation catalysts have been reported by groups of Sun and Llobet1,2,3 but sustainable catalysis is still impaired by catalyst deactivation.4 This dissertation attempts to design robust catalysts through manipulating of the apical coordination sites. Chapter 2 uses phosphorus in the primary coordination sphere to create stronger axial ligand-ruthenium bonds;5 Chapter 3 uses a chelating macrocyclic ligand to reduce the chance of ligand loss. Chapter 4, focuses on the hydroamination of C-C multiple bonds as the most atom-efficient method for the introducing of nitrogen atoms into organic molecules.