[en] The optical properties of the ordered defect compound CuIn₃Te₅ which crystallizes in a chalcopyrite-related structure have been studied by absorption and photoluminescence (PL) techniques. Optical absorption measurements show that the band gap energy E_G varies from 1.078 to 1.040 eV between 10 and 300 K. It is found that the variation of E_G with temperature is mainly due to the contribution of optical phonons with a characteristic energy of about 16 meV. The PL measurements, carried out between 4 and 100 K with laser excitation intensities in the range from 1 to 400 mW, reveal that the main PL band is due to a donor-acceptor recombination between donor and acceptor defect levels that have activation energies of 60 and 30 meV, respectively. These donor and acceptor states are tentatively assigned as originating from indium atoms on copper sites and copper vacancies, respectively