The optical and scintillation properties of undoped, Sb-doped, and Tl-doped Cs2CdCl4 single crystals were investigated. We chose Sb3+ and Tl+ as the dopants of (ns)2-type electronic configurations. In the photoluminescence and scintillation spectra of undoped Cs2CdCl4, three emission peaks were observed. The scintillation decay-time constants were small (1.2 and 13 ns) and light yields were low (several tens of photons/MeV). In contrast, Sb3+- and Tl+-doped Cs2CdCl4 showed s–p transitions of the dopant ions, and the light yield was larger than that of undoped Cs2CdCl4 (625 and 1000 photons/MeV, respectively). Tl-doped Cs2CdCl4 showed relatively large scintillation decay-time constants (270 ns) because of slow energy transfer from the host to Tl+. On the other hand, Sb-doped Cs2CdCl4 showed significant afterglow behavior and three thermally stimulated luminescence (TSL) glow peaks (93, 168, and 238 ℃) with good linearity with respect to the X-ray dose. In conclusion, the light yield of undoped Cs2CdCl4 can be enhanced by doping with Sb3+ and Tl+; TSL characteristics are achieved by doping Sb3+.