Humidity sensing is critical in environmental and industrial spaces to monitor air conditions for the wellbeing of the human population and to ensure favorable industrial processes such as storage and performance. In this work, we utilize room temperature ionic liquids (RTILs) as novel sensing elements toward the development of a robust electrochemical humidity sensor for integration in semiconductor technology. For this study, we report and discuss the performances of a non-fluorinated RTIL vis-a-vis a fluorinated RTIL, MMIM [MeSO 4 Rising environmental concerns have led to the development of sensors to monitor environmental conditions such as CO 2 , VOC's, particulate matter, temperature, and relative humidity (RH). Humidity sensing finds its usage in a broad range of applications for indoor air quality monitoring in HVAC systems and automobiles, weather monitoring in meteorological stations, greenhouse gas monitoring systems, and textile quality monitoring. Three basic sensor types that have been widely used in commercial and industrial space are capacitive, resistive, and thermal humidity sensors.1 Over the years, variety of sensing materials such as ceramics, semiconductors, polyelectrolytes, and polymers have been explored and utilized in humidity sensors.2 Current challenges faced in humidity sensing are sensor drift, accuracy and reproducibility at increased humidity, response time of the sensor, power consumption, and long-term usability.3 These challenges necessitate the development of a new material system for next generation humidity sensing.We employ a unique sensing material system-Room temperature ionic liquid (RTIL) to develop a robust humidity sensor toward making it suitable for commercial applications. Room temperature ionic liquids (RTILs) are a class of materials that have been studied for over a century. They have been shown to be useful in several different applications from gas sensing to protein stabilizers in biological experiments.4,5 Their highly ionic nature, wide electrochemical window, and ideal thermal and physical properties (See Table I) are ideal for the development of new electrochemical based humidity sensor. 4 This class of materials consists of two major components; an organic cation and inorganic anion. These two components can be tuned depending upon what application the material is being investigated. Bridgeman et al. have previously demonstrated a calorimetric humidity sensor using ionic liquid membranes for food and pharmaceutical quality monitoring.7 Due to the pure ionic nature of RTILs, when a voltage is applied, this material has shown promise as a potential electrochemical based sensor. The innovation of this study is to interface an RTIL with a sensing platform which results in the formation of multi stack electrochemical double layer (EDL). 8,9 The charge distribution in the EDL as a result of water adsorption is studied through an AC = These authors contributed equally to this work.* Electrochemical Society Student Member. z E-mail: shalini.prasad@utdallas.ed...