Novel film polymeric composites based on the non-photoconducting polyvinyl butyral with heterometallic complexes (NH4)(4)(n){[Cu(en)(H2O)][P2Mo5O23]}(n)center dot 3.5nH(2)O (1) and (NH4)(2)(n){[Cu(en)(2)][Cu(en)(H2O)][P2Mo5O23]}(n)center dot 3nH(2)O (2) [en = ethylenediamine] have been prepared. Both compounds are similar and contain Strandberg anions [P2Mo5O23](6-) linked to Cu-diamine species. The main structural difference between complexes is the presence of additional bridging [Cu(en)(2)] fragments in 2, which provide an extra connectivity between the neighboring polyoxometalates. However, the different saturations and relaxation times of the photoresponse, as well as different activation energies, are shown. The variability of the photoconducting properties can be explained by the influence of a chain rigidity on the transport of non-equilibrium charge carriers.