The outer valence Green's function (ΣOVGF3), quasiparticle third order (Σq3), and full third order (Σ3) decouplings of the bi-orthogonal dilated electron propagator were developed and tested for the first time for molecular resonances by applying these decouplings to investigate the 2ΠCO-, 2ΠgN2-, and 2ΠgC2H2-shape resonances. Overall, the resonances energies and widths obtained using the third and the second order decouplings are close to each other and to those obtained from the zeroth order decoupling.