Trivalent rare earth (RE³⁺) ions have been used as an activator in laser host materials and in a wide variety of photonic applications. Of the competing hosts, one of the most well studied and successful host has been yttrium aluminum garnet Y₃Al₅O₁₂ (YAG). In comparison to YAG, yttrium oxide (Y₂O₃) has shown promise as a potential laser medium due to its excellent optical, thermal and mechanical properties. As single crystals, Y₂O₃ system can be extremely difficult to grow due to the high melting temperature (∼2200°C) of the host. Alternatively, ceramic and nanocrystalline forms of Y₂O₃ have contributed to renewed interest in the material as laser host and more recently in biological and other photonic applications due to simplicity of fabrication. This work focuses on four RE ³⁺ ions, namely erbium, neodymium, holmium, europium doped into Y ₂O₃ and are selected due to their multi-frequency absorption properties and visible to near infrared emission characteristics. The chosen nanocrystalline material are embedded or coated in polymers that are biocompatible resulting in visible to near infrared fluorescent polymers. These materials are characterized through morphology studies and spectroscopic analyses of the absorption and emission spectra. Judd-Ofelt (J-O) and Crystal-Field (CF) techniques are applied to the systems and the results are compared to single crystal and ceramic forms and in some cases these analyses are reported for the first time for this host. Results of these analyses show that the addition of near infrared emitting rare earth nanocrystals to these polymers offers an attractive application to their existing biological applications.