A　highly　efficient　catalytic　system,　CuSO4·5H2O/1-(4-methoxyphenyl)-3-phenylthiourea,　for　the　copper(I)-catalyzed　azide–alkyne　cycloaddition　reaction　(CuAAC)　was　discovered.　In　the　above　catalytic　system,　substituted　thiourea　acts　both　as　a　reductant　and　a　ligand.　CuSO4·5H2O/1-(4-methoxyphenyl)-3-phenylthiourea　is　both　an　economical　and　efficient　catalyst　for　the　CuAAC　reaction.　In　addition,　the　new　catalytic　system　has　advantageous　features　including　mild　and　green　reaction　conditions,　and　broad　substrate　compatibility.　A　variety　of　1,4-disubstituted　1,2,3-triazoles　have　been　prepared　with　good　to　excellent　yields　with　the　CuSO4·5H2O/1-(4-methoxyphenyl)-3-phenylthiourea　catalytic　system　in　aqueous　solution.　©　2017　Elsevier　Ltd