The bi-acidic properties of the low-coordinated ?2- phosphorus in the stable 1,3-azaphosphole substructure might be strengthened compared to benzazaphospholes by anellation with electron- withdrawing heterocycles. Pyridine-anellated 1,3- azaphospholes without N-bridgehead are not yet known to the best of our knowledge. The unsymmetric bi- charge density distribution in pyrido-anellated heterocycles may lower the kinetic stability and thus increase the reactivity, as indicated by the easier thermal decomposition of pyrido- as compared to benzo-anellated N-heterocyclic silylenes, germylenes and stannylenes. Therefore, the chemistry of electron-withdrawing anellation should be studied by means of pyridine anellation and additionally symmetric electron-withdrawing anellation with a quinoxaline ring. Anellated 1,3-azaphospholes of this type, which should present efficient bi- acceptor ligands, are still unknown to the best of our knowledge in sznthesis, coordination chemical behaviour and finally in catalysis.