<p>A potentiometric poly(vinyl chloride) (PVC) membrane benzydamine (BZD)-selective sensor based on potassium tetrakis(4-chlorophenyl)borate (KT<i>p</i>ClPB) as an electroactive material was fabricated with a broad linear range and ultra-low detection limit in a straightforward, cost-effective, and efficient manner. As an outcome of the membrane optimization research, it was found that the membrane composition that exhibited the best potentiometric performance metrics among the studied membrane compositions was 32.0% (<i>w/w</i>) PVC, 67.0% (<i>w/w</i>) <i>o</i>-NPOE (<i>o</i>-nitrophenyloctyl ether), and 1.0% (<i>w/w</i>) KT<i>p</i>ClPB. The sensor displayed a linear response to BZD within the concentration range of 1.0 × 10⁻⁸ to 1.0 × 10⁻² mol L^-1, achieving a detection limit of 5.0 × 10^− 9 mol L^-1 and a sensitivity of 56.6 mV decade⁻¹. The electrodes possessed a rapid response time of about 10&#xa0;s. The sensor’s analytical capability was demonstrated by accurately quantifying the benzydamine content in multiple pharmaceuticals with benzydamine as the active component, yielding high recovery values.</p>