Pyrolysis under air at 800 A degrees C, of the cyclic N3P3[OC6H4PPh2 center dot Mn(CO)(2)(eta-MeC5H4)](6) (1) and the polymer {[NP(O2C12H8)](0.5)[NP(OC6H4COOPr (n) )(OC6H4PPh2 center dot Mn(CO)(2)(eta-MeC5H4))](0.5)} (n) (2) phosphazene with pendant OC6H4PPh2 center dot Mn(CO)(2)(eta-MeC5H4) units affords nanostructured Mn2P2O7. The morphology of the pyrolytic products is highly dependent on the phosphazene support. Dense structures were observed from pyrolysis of cyclic (1) while most porous materials were obtained from pyrolysis of polymer (2). The new polymeric complex (2) was prepared from reaction of the phosphine containing polymer {[NP(O2C12H8)](0.5)[NP(OC6H4COOPr (n) )(OC6H4PPh2)](0.5)} (n) and the photochemically generated [Mn(THF)(CO)(2)(eta-MeC5H4)] and was fully characterized.