Exposure of solutions of Tb(N(SiMe(3))(2))(3) with SiCl(NEt(2))(3) in tetrahydrofuran to dry ammonia results in polymeric xerogels. Heating these gels in ammonia leads to amorphous Tb:SiN(x) phosphors that exhibit bright green luminescence under UV irradiation. MAS-NMR and combustion analysis reveal that the phosphors are silicon nitride materials analogous to those typically produced by sol-gel routes. Photoluminescence behavior is similar to that of Tb:SiN(x) or Tb:SiO(2) films produced by ion implantation that show good electroluminescence activity.