The essential part (including all the non-hydrogen atoms except two methyl carbons) of the mol-ecule of the title compound, C21H26N4O5, lies on a mirror plane, which bis-ects the t-butyl groups. The conformation of the C=N bond of this Schiff base compound is E, and there is an intra-molecular N-H⋯O hydrogen bond present, forming an S(6) ring motif. In the crystal, mol-ecules are linked via O-H⋯O hydrogen bonds, forming zigzag chains propagating along the a-axis direction. There are no other significant inter-molecular contacts present.
Keywords: 2,4-dinitrophenylhydrazine; 3,5-di-tert-butyl-4-hydroxybenzaldehyde; crystal structure; di-tert-butylphenol; dinitrobenzene; hydrazine; hydrogen bonding.