The optical properties of the one-dimensional organic conductor (perylene) ₂Pt(mnt) ₂ and its Au analogue have been investigated at ambient and low temperatures. The spectra along the stacks of the molecules show a simple Drude behavior with no detectable influence of electron-electron interactions. Basing on the spectra for different polarizations an assignment of the vibrational modes is made. Perpendicular to the stacks, a wide band observed in the mid-infrared range evidences a charge transfer between perylene and anion stacks. The electronic properties are discussed in comparison with other quasi-one-dimensional synthetic metals.