Glasses of the 0.5Er(3+)/2.5Yb(3+) co-doped (40Bi(2)O(3)-20GeO(2)-(30 -x)PbO-xZnO-10Na(2)O system where x = 0.0, 5, 10, 15, 20, 25, and 30 mol%) have been characterized by FT-IR spectroscopy measurements to obtain information about the influence of ZnO-substituted PbO on the local structure of the glass matrix. The density and the molar volume have been determined. The influences of the ZnO-substituted PbO on the structure of glasses have been discussed. The dc conductivity measured in the temperature range 475-700 K obeys Arrhenius law. The conductivity decreases while the activation energy for conduction increases with increase ZnO content. The optical transmittance and reflectance spectrum of the glasses have been recorded in the wavelength range 400-1100 nm. The values of the optical band gap E (opt) for all types of electronic transitions and refractive index have been determined and discussed. The real and imaginary parts epsilon(1) and epsilon(2) of dielectric constant have been determined.