This paper presents a single compound complementary split-ring (SC-CSRR) to induce dual resonance frequencies for simultaneously measuring the permittivity and thickness of a material. The dual resonance frequencies, fL and fH, are generated using two distinct resonator current lengths in a single CSRR. By using the proposed methods, the ratio of dual resonance frequency relationship can be used to determine the thickness of the material under test (MUT); the permittivity is linearly related to the resonance frequency. A simple and low-cost SC-CSRR measurement method for assessing the permittivity of materials in a compact area was numerically analyzed and experimentally verified. Testing yielded average measurement errors of 6.26% and 4.63% for the thickness and permittivity, respectively.