Abstract The two imidazole rings in the title compound, CsHt0N40, are almost coplanar, having an angle of 2.3 (2) about the C---C bond connecting the rings. The conformation adopted is such that the nitrogen sub-stituents (-H and-CH2CH2OH) are in a trans orien- tation. The molecules are connected by intermolecular O--H... O and N--H... N hydrogen bonds to yield an arrangement of pairs of molecules reminiscent of side-by-side stacks of ...