Six imidazolium-based room temperature protic ionic liquids (PILs) have been synthesized by the process of proton transfer from hydroxy acids (Bronsted acids) to substituted imidazole (Bronsted base). The PILs were characterized by UV, Infrared and Nuclear Magnetic Resonance and GC-MS spectroscopes. Their anti-microbial activities were determined using the well-diffusion method. All six PILs were toxic to Ecoli streptomyces bacillus, while 2-methyl imidazolium lactate showed high anti-microbial activity against a wide range of human pathogens