Benzodiazepines (BZs) are a class of regulated psychoactive drugs prescribed for various clinical condition including insomnia, anxiety, withdrawal syndrome, etc. Designer BZ are the chemical derivatives of the BZ drugs with little (or even no) toxicological and pharmacological data and approval for clinical practice. Owing to the unknown toxicological behaviour and prompt association in numerous drug facilitated crimes the designer BZ has emerged as serious hazard to public health and safety. In this work, we exercised the interfacial ion transfer characteristics of four designer BZ (Clonazolam, Diclazepam, Flualprazolam, Flubromazolam) at the electrified liquid-liquid interface (eLLI) to explore their physiochemical parameters such as molecular partitioning coefficients, distribution constants and concentration fractions across the conventional pH range. A linear sweep voltammetric analysis of each BZ drug at eLLI delivered key analytical parameters such as the linear detection range, limits of detection, quantification and voltametric sensitivity which are found to be in the range of , respectively. Furthermore, the eLLI based designer BZ sensor demonstrates admirable analytical performance towards the on-spot detection of the BZ spiked in three different beverage samples. On top, the configured eLLI based BZ sensor is promising towards discriminating two BZ drugs with identical chemical cores at lower concentrations.