Structural, photoluminescence, dielectric, and ferroelectric properties of lead-free perovskite Pr3+-doped xK(0.5)Bi(0.5)TiO(3)-(1 - x)Na0.5Bi0.5TiO3 (x = 0-1.0) thin films were studied. The thin films were prepared by a chemical solution deposition method combined with a rapid thermal annealing process at 700 degrees C. We observed that the thin film with x = 0.15, corresponding to the morphotropic phase boundary in the solid solution ceramics or single crystal bulk counterparts, showed a very large dielectric constant and a high remanent polarization, as well as a strong red emission at 611 nm assigned to D-1(2) -> H-3(4) transitions of the Pr3+ ions. In addition, this study also indicates that the morphotropic phase boundary in xK(0.5)Bi(0.5)TiO(3)-(1 - x)Na0.5Bi0.5TiO3 thin films might be probed by photoluminescence probe of Pr3+ ions because the photoluminescence of Pr3+ ions is very sensitive to the phase structure changes.