The development of antibiotic resistance has also increased the interest in hydrazones. In this paper, we describe the new aroyl hydrazone and its Cu(II) complex, which we synthesized. Aroyl hydrazone (HL) was prepared by the condensation reaction of 3‐hydroxy‐2‐naphthoic hydrazide with di‐2‐pyridyl ketone. Ligand (HL) and its transition metal complexes [CuL2] (1), have been characterized by elemental analysis, FT‐IR, UV‐Vis., 1H‐NMR, and LC–MS techniques. The molecular structure of HL, whose crystal structure could not be obtained, was elucidated by the DFT/B3LYP/6‐311+G(d, p) method. The optimized molecular structure, total energy, molecular orbital energy values, molecular electrostatic potential map, reactivity parameters, and interaction with DNA bases were investigated. Theoretical UV‐vis spectra of HL were obtained with TD‐DFT in different solvent environments. In addition, the ligand and its complex were examined for their antimicrobial activity against pathogenic microorganisms by using a minimal inhibitory concentration method (MIC). It was determined that the [CuL2] (1) complex was generally moderately active. It was also observed that the [CuL2] (1) complex was more active than the HL.