A　family　of　functionalized　MIL-68(In)　have　been　successfully　synthesized　and　applied　to　photoreduction　of　Cr(VI)　aqueous　under　simulated　sunlight　(280　nm　2BDC,　H2BDC-NH2,　H2BDC-NO2　and　H2BDC-Br)　on　photocatalytic　performance　of　MIL-68(In)-X　(X　=　H,　NH2,　NO2,　Br).　Further　experimental　results　demonstrated　that　the　photoactivities　of　the　obtained　MIL-68(In)-X　have　been　greatly　affected　by　the　electronic　effect　of　ligand　substituent.　That　is,　the　reaction　rates　obtained　by　functionalized　MIL-68(In)　have　been　linearly　associated　with　the　Hammett　coefficients　of　different　substituents.　More　significantly,　MIL-68(In)-NH2　has　also　exhibited　outstanding　performance　in　a　co-existed　model　system　(Cr(VI)/dyes),　which　represents　a　first　example　to　use　the　In-based　MOFs　as　bifunctional　photocatalysts.　It　is　hope　that　this　work　not　only　represents　the　structure-property　relationships　on　photocatalysis　in　MOFs,　but　also　promotes　further　interest　in　design　and　construction　of　more　efficient　MOFs-based　photocatalysts　for　environmental　remediation.　©　2018　Elsevier　B.V.