diversity of solid forms, two polymorphic pairs of the enol‐imino (D1 a and D1 b) and keto‐
amino (D2 a and D2 b) desmotropes. The isolated phases, identified by IR spectroscopy, X‐
ray crystallography, and 13C cross‐polarization/magnetic angle spinning (CP/MAS) NMR
spectroscopy, display essentially planar molecular conformations characterized by strong
intramolecular hydrogen bonds of the O H⋅⋅⋅ N (D1) or N H⋅⋅⋅ O (D2) type. A change …