<p>This research investigates the effect of partial substitution of silver (Ag) and strontium (Sr) on the structural, electrical, and insulating properties of the Bi₂₋ₓAgₓBa₂₋γSrγCa₂CO₂Cu₃O₁₀ + <i>δ</i> compound. The samples were prepared using the solid-state reaction method, followed by sintering and double annealing to enhance their properties. X-ray diffraction (XRD) analysis revealed a tetragonal crystal structure, with the c-axis length increasing slightly when strontium concentration was raised from y = 0.1 to y = 0.3. However, the increase in Sr concentration resulted in a slight decrease in the unit cell volume from 461.69 ų to 460.37 ų, indicating that higher Sr content did not significantly improve the material’s properties. The critical temperatures (<i>Tc</i>) of the samples were measured, with <i>Tc</i>(1) = 139.2 K and <i>Tc</i>(2) = 172.2 K for the sample with x = 0.2 and y = 0.1. For the sample with x = 0.2 and y = 0.3, <i>Tc</i>(1) decreased slightly to 138.3 K and <i>Tc</i>(2) to 168.8 K, suggesting a limited effect of Sr on improving superconducting properties. Dielectric measurements across frequencies from 100 Hz to 1 MHz showed a reduction in dielectric constants and loss tangent with increasing frequency, indicating the dominance of electronic polarization at higher frequencies. This research is significant in advancing the development of high-temperature superconducting materials. It provides new insights into the effect of Ag and Sr substitution on the superconducting and dielectric properties, contributing to the optimization of these materials for applications in energy storage, superconducting transportation, and quantum computing.</p>