AbstractErbium ion (Er3+) doped materials are of great interest for their optical amplification, lasing and frequency up-conversion properties. When preparing such materials, a major problem that often arises is the formation of Er-rich oxide clusters inducing optical quenching. The materials prepared at low Er3+-ion concentrations to overcome the problem have severely reduced the optical yield. Such clustering might be avoided by preparing suitable precursors. If Er is encapsulated with proper materials, clustering can be avoided and higher doping levels can be achieved. In this study, erbium phenoxide complex was obtained by metathesis reaction of erbium chloride (ErCl3) with potassium phenoxide (KOPh). And heterometallic complexes were also synthesized by encapsulation of the Er with Al or Ti derivatives. The complexes were characterized by elemental analysis, infrared and nuclear magnetic resonance spectroscopic analysis. Their crystal structures were determined by X-ray single crystal diffraction analysis. In addition, the Er-doped organic-inorganic matrices using the erbium complexes were investigated about their optical properties.