Lanthanide ions (Ln) possess unique photophysical and magnetic properties, finding application in magnetic and optical technologies, both at bulk and molecular scales. While bulk systems offer scalability and high stability, molecular systems allow exquisite structural and electronic control, leading to extraordinarily effective molecules. Molecular design has produced record breaking molecular magnets and highly emissive complexes. Combining multiple, different Ln in a molecular species is desirable to design multimetallic systems for sensing, optics, and quantum information science. However, the ionic bonding of Ln and their resultant chemical similarity makes selective synthesis of heteromultimetallic molecules challenging.