Temperature induced reversible polymorphic phase transformations in a bis-hydrazone compound

Two reversible polymorphic phase transformation of 2,3-butanedione, 2,3- bis[4,4′-bis(diethylamino)benzophenone hydrazone] (DEBH) have been identified in DSC experiment. Topotactic phase transformation of three polymorphs has been observed in variable temperature Single Crystal X-ray Diffraction experiment. The reversible phase transformation of bulk material has been confirmed by Powder X-ray diffraction study.