A novel Cu (Ⅱ) complex of 1-phenyl-3-methyl-4-acyl-5-pyrazolone was synthesized and crystallogra- phically characterized. The single-crystal structure of the complex reveals that the crystal belongs triclinic, space group P1 with cell parameters a=0.938 7(4) nm, b=1.124 4(5) nm, c=1.222 3(5) nm, α=99.538(7)°, β=104.049(8)°, γ=113.806(6)°, and Z=2, V=1.093 3(8) nm3. Cu(Ⅱ) ion is coordinated by two 1-phenyl-3-methyl-4-acyl-5-pyrazolone ligands, and one methanol molecule giving a coordination number of five, the coordination polyhedron around Cu(Ⅱ) ion can be described as a square pyramid. Two complex units link to each other through the hydrogen-bonding interactions to form a dimer. Meanwhile, a staircase-like layer structure was built up by offset face-to-face π…π stacking interactions and weak interactions between the dimers.
