Abstract
We prove that the upper electronic bands of κ-phase BEDT-TTF salts are adequately modeled by a tight-binding lattice with one site per cell. The band parameters are derived from recent ab initio calculations, getting a very simple but extremely accurate one-electron picture. This picture allows us to solve the BCS gap equation adopting a real-space pairing potential. Comparison of the resulting superconducting properties with experiments points to isotropic s0-pairing. Residual many-body or phonon-mediated interactions offer a plausible explanation of the large variety of physical properties observed in κ-phase BEDT-TTF salts.