A procedure to synthesize diphenylanthracene (DPA) with siloxane substituents for use as a sensitizer in triplet-triplet annihilation upconversion (TTA-UC) was developed. In TTA-UC, photons excite sensitizer molecules to a triplet excited state, then the sensitizer transfers the absorbed energy to an annihilator molecule. The annihilator emits a photon of a higher energy than the photons absorbed by the sensitizer. TTA-UC has potential applications in solar energy, displays, and photocatalysis as it utilizes non-coherent radiation to generate light with increased energy. We introduced phase segregation in bulk by attaching siloxane chains with the goal of maximizing the annihilator-sensitizer interaction, thereby increasing TTA-UC efficiency.