We investigate the magneto-optical and magnetic properties of two quaternary diluted magnetic semiconductor alloys, Cd1−x−yMnxCryTe and Cd1−x−yMnxCoyTe, with fixed Mn concentration x ∼ 0.37 and, respectively, with concentrations of Cr in the range 0 < y < 0.07 and Co in the range␣0 < y < 0.009. The introduction of Cr and Co leads to very different behaviors, including the occurrence of ferromagnetic order in the case of Cd1−x−yMnxCryTe. We discuss the possible origins leading to the observed behaviors.