Combined solutal and thermal buoyancy–thermocapillary convection in a square open cavity is studied numerically in the present article. The Forchheimer–Brinkman-extended Darcy model is used in the mathematical formulation for the porous layer and the COMSOL Multiphysics software is applied to solve the dimensionless governing equations. The governing parameters considered are the thermal Marangoni number, −1000 ≤ Ma_T ≤ 1000, the Darcy number, 10−5 ≤ Da ≤ 10−2, the porosity of porous medium, 0.4 ≤ ε ≤ 0.99 and the Lewis number, 10 ≤ Le ≤ 200. It is found that the global heat and solute transfer rate decreases by reducing the counteracting surface tension force and increases by augmenting the surface tension force. The minimum values of the global heat and solute transfer rate were obtained about Ma_T = −90 for the all porosities
