Group II-VI narrow band gap compounds CdTe ZnCdTe and CdSeTe are known as the most suitable semiconductor materials for the room temperature gamma- and X-ray radiation detectors. In this work we investigated electronic properties of a quaternary compound ZnCdSeTe. Cl Cu Pr Er and oxygen doped host materials were synthesized from the grinded mixture of 6N purity ZnTe CdTe and CdSe by the help of CdCl2 flux. Precautions were applied to achieve an uniform doping and high quality of the crystal surfaces. Residue phases after the thermal treatments were removed by the help of a vacuum annealing. It was found that Zn increases a substitutional solubility of dopants in ZnCdSeTe and thus promotes optoelectronic properties of the ZnCdSeTe alloy. Cl substitutes Te whereas Cu and rare earth elements substitute Zn in ZnCdSeTe. Fabricated polycrystalline samples showed a high performance from NIR via VIS and UV to X-ray band. High stability good linearity and performance of samples was measured under X-ray excitation of Cu Kα 1.54056 Å at 40 kV.