3-Phenylpropenal thiosemicarbazone hydrate C₆H ₅-HC=CH-CH=N-NH-C(S)-NH₂ • H₂O (HL • H₂O, I) and two chelates [Ni(L)₂] • nCH₃OH (II) and [Zn(L)₂] (III) are studied by X-ray diffraction. The crystals of I are orthorhombic: a = 6.227(1) Å, b = 7.763(2) Å, c = 25.585(5) Å, β = 90°, space group P2₁2 ₁2₁, Z = 4, R = 0.0426. A nonplanar molecule of I has an E conformation. The crystals of II are triclinic: a = 6.551(2) Å, b = 10.752(3) Å, c = 10.885(3) Å, α = 64.751(5)°, β = 82.753(5)°, γ = 89.857(5)°, space group, Z = 1, R = 0.0661. In a centrosymmetric molecule of II, the central atom coordinates two deprotonated ligands L through the immine nitrogen atom and thioamide sulfur atom at the vertices of a distorted square. The crystals of III are monoclinic: a = 25.342(2) Å, b = 9.150(2) Å, c = 21.340(3) Å, α = 90°, β = 111.84(2)°, γ = 90°, space group C2/c, Z = 8, R = 0.0556. In a molecule of complex III, two deprotonated bidentate ligands L are coordinated by the zinc ion through the immine nitrogen atoms and thioamide sulfur atoms to form a distorted tetrahedron at the central atom. In both II and III, ligand L after coordination by the metal ion changes the E conformation with respect to the N(1)-C(2) bond for the Z conformation. In crystals I-III, molecules are packed to form infinite layers parallel to the planes (001) and (010)