Entropy generation of a steady Jeffrey fluid flow over a deformable vertical porous layer is analysed with consideration of a first-order chemical reaction and thermal diffusion. The porous material is modelled as a homogeneous binary mixture of fluid and solid phases where each point in the binary mixture is occupied concurrently by the fluid and solid. The combined phenomenon of solid deformation and fluid movement is taken into account. The impact of relevant parameters on the fluid velocity, solid displacement, temperature and concentration profiles is discussed. It is noticed that the Jeffrey fluid parameter enhances the entropy generation number, fluid velocity and solid displacement profiles, but a reverse effect is seen for the Bejan number. Further, entropy generation, fluid velocity and solid displacement reduce due to the higher estimates of the chemical reaction parameter, while the Bejan number enhances.