A new complex compound, catena-triglycinium-µ-chlorido-tetrachloridocuprate(II) glycine co-crystal (or glycine-triglycinium pentachlorocuprate), {(C2H6NO2)3CuCl5·(C2H5NO2)}n, was synthesized and studied by single crystal X-ray diffraction (SC XRD) and mid-range infrared spectroscopy. The compound crystallizes in a non-centrosymmetric triclinic P1 space group with lattice parameters a = 5.1277(2) Å, b = 9.1412(6) Å, c = 12.2023(5) Å, α = 101.407(4)°, β = 97.460(3)°, γ = 105.832(4)°, Z = 1. The unit cell contains four glycine ions—three glycinium cations and single zwitter-ion—linked through hydrogen bonds network. The anionic part of the compound is presented by infinite chains [CuCl6]n of distorted (elongated) octahedra, connected by vertices and alternating direction of elongated axis. Positions of hydrogen atoms were refined using geometry optimization via density functional theory (DFT) approach. Thermogravimetric analysis (TGA) showed the title compound to be stable in air atmosphere up to ∼ 388‒393 K and decomposes upon further heating.