Three metal complexes, [Re(bpy)(CO)3(CN-t-Bu)]Cl (1) (bpy = 2,2-bipyridine), Bu4NIr(ppy)2(CN) 2 and Ir(ppy)3 (3) (ppy = 2-phenylpyridine, Bu4N = tetrabutylammonium cation) were evaluated as oxygen sensors in poly((n-butylamino)thionylphosphazene) matrices. The phosphorescent dyes 2 and 3 exhibited exponential decays both in degassed solution and in the polymer films, with somewhat longer lifetimes in the polymer film. All three dyes gave linear Stern-Volmer plots, but 1 was rather sensitive to photodecomposition. The slopes of the Stern-Volmer plots for these dyes were compared to those measured previously for platinum octaethyl porphine (PtOEP) and ruthenium tris-diphenylphenanthroline chloride ([Ru(dpp)3]Cl2. The effective capture radius for quenching by oxygen were 1.7 nm for 2 and 2.7 nm for 3, relative to a value of 1.0 nm for PtOEP. Thus dye 3 is 2.7 times more sensitive to quenching by oxygen than PtOEP and more than 5 times more sensitive than ([Ru(dpp) 3]Cl2.