The electronic and nuclear structures of a series of [Cu(2,9‐X‐phen) 2 ] copper(I) complexes (phen = 1,10‐phenanthroline; X=H, F, Cl, Br, I, Me, CN) in their ground and excited states is investigated by means of density functional theory (DFT), time‐dependent (TD‐DFT) methods and Born‐Oppenheimer molecular dynamics. The Gibbs free energy profiles, associated to S 1 and T 1 electronic states, which connect the four degenerate minima induced by ligand flattening and symmetry breaking when exciting the molecule are calculated as well as transition state structures and related energy barriers. Three nuclear motions drive the photophysics, namely the coordination sphere asymmetric breathing, the well known flattening and the bending of the phen ligands. This theoretical study reveals the limit of the static picture based on potential energy surfaces minima and transition states for interpreting the luminescent and TADF properties of this class of molecules. Whereas only small asymmetric Cu‐N bonds breathing are involved in electronic delocalization over one or the other phen ligand, the three nuclear movements participate to the formation of the flat conformers. This leads to negligible energy barriers whatever the ligand X for the first process and significant ligand dependent energy barriers for the second one.