Changes in solvation of samarium diiodide (SmI2) can significantly alter the interaction between a ligand and metal. Addition of the appropriate “crown ether” to SmI2 in acetonitrile not only stabilizes the ground state complex but also generates a highly luminescent complex. The advantage of direct excitation of lanthanide(II) complexes includes elimination of different deactivation pathways as well as the multi-step syntheses involved in preparing “antenna” ligands necessary for producing luminescent lanthanide(III) complexes. We demonstrate how controlling the coordination sphere of SmI2 through changes in solvation induces remarkable changes in property both in the ground and excited states. Providing a chelating ligand for SmI2 in a solvent incapable of displacing it significantly enhances the luminescent properties of Sm(II) by: 1.) encapsulating the metal through a strong metal-ligand interaction and 2) decreasing the frequency of solvent collision. This study led to the discovery of the longest reported excited-state lifetime reported for a Sm(II) complex in solution.