The electrochemistry of a series of phosphazene polymers {[Ph(Me)=N] [Ph{R′RC(OH)CH }P=N] } where R′ is (η C H )Fe(η C H ) with varying degrees of ferrocene substitution (3, x = 0.94, y = 0.06, R = H; 4, x = 0.80, y = 0.20, R = H; 5, x = 0.64, y = 0.36, R = CH ; 6, x = 0.56, y = 0.44, R = H) has been investigated in CH Cl and as films evaporatively deposited on the electrode surface. The E of the ferrocene units (463 ± 12 mV vs Ag/AgCl) for the polymer dissolved in CH Cl is essentially independent of the degree of substitution and background electrolyte. Diffusion coefficients (D ) for 3–6 were determined using a combination of rotating-disk voltammetry and chronocoulometry. A trend of increasing D with increasing degree of ferrocene substitution suggests a dual mode of transport, where both physical diffusion and electron hopping are occurring. Polymer films were deposited by evaporation on Pt and glassy C electrodes, and E values were measured at 470 ± 10 mV (Ag/AgCl) when the films were immersed in 0.1 M TBAP, (TBA)PF , TEAP, or (TEA)Br in acetonitrile or in TBAP or (TBA)PF in CH C1 . Film-casting parameters were found to influence polymer swelling and charge-transport numbers (D C, which vary with the degree of ferrocene substitution from 1 × 10 to 5 × 10 mol/(cm s ). © 1993, American Chemical Society. All rights reserved. x 2 y n 5 4 5 5 3 2 2 ½ 2 2 o o ½ 6 6 2 2 o 5 5 ½ −7 −9 2 ½