The determination of the energies and TDMs has been done using the state-averaged RASSCF method and the ANO-RCC quadruple-ζ basis set. The active space comprised 6 electrons distributed over 4 orbitals including two bonding π-like ones mixed with the oxygen lone-pair, nitrogen lone-pair, and the π * orbital of the CH 2 =N fragment, see Figure in the Supporting Information. The Cholesky decomposition used a standard threshold of 10 -4 .