Electron transport coefficients in gas discharges for CF3I-Ne and Cl2-Ne mixtures were analysed and calculated by a two-term approximation of the Boltzmann equation in a wide E/N range (ratio of the electric field E to the neutral number density N). The electron transport coefficients include the electron drift velocity, density-normalized longitudinal diffusion coefficient, and density-normalized effective ionization coefficient. These results are calculated for the first time over a wide range of E/N values. The limiting field strength values of E/N, (E/N)lim, for these binary gas mixtures were also derived and compared with those of the pure SF6 gas. The (E/N)lim values of CF31-Ne mixture gas were greater than those of the pure SF6 gas with the CF3I concentration equal to approximately 70 percent. These binary gas mixtures, therefore, may be considered to use in high voltage and many industries depending on mixture ratios and particular applications of gas and electrical equipments.