The absorption spectrum of benzene–iodine and hydrogen sulfide–iodine was studied at 20°K in argon, krypton, xenon, methane, nitrogen, and sulfur hexafluoride in the spectral range of 2300 to 4500 Å. In addition to the component spectra, strong bands were observed around 2800 Å in all solvents. They are assigned to the electronic charge-transfer transitions of the electron donor-acceptor systems benzene–iodine and hydrogen sulfide–iodine, respectively. The bands are broad and exhibit coarse as well as fine structure. The latter corresponds closely to the ground-state vibrational frequency of iodine. While the solvent shifts in the benzene–iodine system follow the predictions for the heavy-atom effect, the shifts of the hydrogen sulfide–iodine bands appear reversed. The half-width of the bands increases, for benzene–iodine, with increasing polarizability, but decreases for the hydrogen sulfide–iodine system. The absorbance of the charge-transfer bands of the hydrogen sulfide system are stronger than those of the benzene system, and both are greater than that of the a–X system of benzene. The electron-donor spectra seem little perturbed by the presence of the charge-transfer complex. However, a great increase of transition energy and absorbance is noted for the visible transition of iodine. The fine structure of the 3600-Å band of iodine in matrices containing hydrogen sulfide–iodine is 130 cm−1, corresponding well to the vibrational frequency of the B state of iodine.