N,N'-Bis(2,6-diiso-propyl-phen-yl)-N-hy-droxy-formamidine-N,N'-bis-(2,6-diiso-propyl-phen-yl)-N-oxidoformamidinium (1/1).

The title compound, C25H36N2O, crystallized with two independent mol-ecules in the asymmetric unit each with statistical proton disorder within the formamidine backbone, thereby indicating the coexistence of zwitterionic and neutral tautomers. The mol-ecular conformation is described by the dihedral angles between each phenyl ring plane and the formamidine backbone, which are 79.8 (3) and 76.0 (3)°, and by the dihedral angle between the two phenyl ring planes, which is 59.61 (11)°. In the crystal, O-H⋯O and N-H⋯N hydrogen bonds connect the neutral and zwitterionic mol-ecules into cyclic dimers. The methyl groups of one isopropyl residue are statistically disordered.