a b s t r a c tA series of polycrystalline samples of Sr 2 À x IrO 4 (0 r x r0.3) have been synthesized by a solid-state reaction method. The crystal structure of this doped system can be explained on the basis of the extended nature of 5d electrons and strontium vacancies in Sr 2 À x IrO 4 . The analysis of the temperaturedependent resistance of these samples reveals the semiconducting feature, in which the threedimensional variable range hopping (3D-VRH) behavior is observed at temperatures lower than 120 K, the Arrhenius type in intermediate temperatures from 140 K to 200 K, and the two-dimensional (2D) weak-localization at high temperatures from 220 K to 300 K. Correspondingly, temperature-dependent magnetic properties in the range of x r0.30 can be described by the antiferromagnetically ordered spin system.