Visible chemiluminescence in the 5800‐6600 Å region was observed from the Ca+Cl2 reaction in an argon matrix. The longer wavelength doublet progression is assigned as the A2Π3/2, 1/2→X2Σ+ transition of CaCl, with v00= 16189 and 16126 cm−1, respectively. Emission from the vibrationally excited v' = 1 level of the A state was also observed. This is the first observation of resolved spin‐orbit components in matrix chemiluminescent reactions. The progression with v00=16855 cm−1 was assigned as the B2Σ+→X2Σ+ transition of CaCl. Both transitions showed very small matrix shifts in the T2 values. A weak band at 17185 cm−1 was assigned as either the E2Σ→B2Σ+ or the a4Σ+→A2Π transition of CaCl. Ca atomic emission at 4232 and 6574 Å was also observed and it was attributed to the energy transfer processes from excited CaCl radicals.