Three neutral copper(II) complexes [Cu(L)2X] [X = none, N,N-dimethylformamide (DMF)0.5, N,N-dimethylacetamide (DMA)0.5 for 1, 2, and 3, respectively] containing benzotriazole–phenolate ligand HL [HL = 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol] have been synthesized and investigated with single-crystal X-ray diffraction, elemental analysis, and spectroscopic techniques [ESI-MS, IR, UV/Vis, electron paramagnetic resonance (EPR)]. The geometry of complex 1 is distorted square planar, while the isostructural complexes 2 and 3 are pentacoordinated. The redox properties of complex 1 were studied by cyclic voltammetry, and the corresponding one-electron oxidized species was generated and characterized by UV/Vis and EPR. Theoretical calculations were performed to support and rationalize the experimental data. Complex 1 was evaluated for its capability to perform veratryl alcohol oxidation and oxidative cleavage of DNA in DMF and DMSO in the presence of different agents (hydrogen peroxide, ascorbate, dithiothreitol).