ABSTRACTMetal organic frameworks have been recently highlighted as promising materials for heterogeneous catalysts. In this study, MIL‐101, a chromium‐based metal organic framework was synthesized using the solvothermal method and functionalized through sulphation. The catalytic activities of MIL‐101 and sulphated MIL‐101 (MIL‐101s) were tested in the esterification of acetic acid. The conversion of acetic acid increased from 73.7 to 86.2 % after sulphation at 363 K. These results prove that the sulphation of MIL‐101 is an effective way to enhance the acidity and catalytic activity of MIL‐101.The characterization of MIL‐101 and MIL‐101s was performed using FTIR, BET, XRD, TG‐DTA, SEM/EDX, XPS, and potentiometric titration methods. A BET analysis showed that MIL‐101 maintained its porosity after sulphation. The sulphation reduced the surface area and pore volume but increased the acidity.