Efficiency of the photocatalytic reaction decreases due to the recombination of the photogenerated charge carriers. If both the charge carriers are diverted to different surfaces, then the efficiency can be improved further. This is possible with the heterojunction semiconductor photocatalyst with built in chemical potential differences that tend to separate the electron and hole into different region of the catalyst. In the quest to achieve low recombination; in this work, experimental methods and results are reported on the one-pot synthesis of Sm2Ti2O7/SmCrO3 composite semiconductor photocatalyst with heterojunction structure prepared by solid state combustion method. The prepared catalysts are characterized by XRD, DRUV-Vis spectrophotometer, HRTEM, FESEM, PL, XPS and BET surface area measurements. The activity of the prepared catalysts is tested towards the degradation of R6G dye under its natural pH. The rate of degradation of R6G dye by heterojunction photocatalysts is higher than that of single phase. The proposed mechanism for the enhanced visible-light photocatalytic activity composites was proven by photoluminescence (PL) spectroscopy and hydroxyl radicals trapping measurement. (C) 2012 Elsevier B.V. All rights reserved.