For the first time, supported liquid membranes (SLMs) of phthalate-and nitrile-based organic solvents were investigated for electromembrane extraction (EME) of eleven polar and non-polar basic drugs from human plasma (pH 7.4). Several phthalates and nitriles which possess high hydrogen bond acceptor basicity, zero hydrogen bond donor acidity, and certain level of hydrophobicity (3< log P< 5.5) were identified as new and efficient SLMs. The new solvents provided low extraction current, and contained no solvent impurities contaminating the acceptor solution when analyzed by HPLC-UV. Extraction recoveries, kinetics, and even selectivity with diallyl phthalate and dodecanenitrile were similar to 2-nitrophenyl octyl ether (NPOE), although they comprised totally different functional groups. Water penetration into the SLM during EME was investigated for the first time and analyzed by Fourier transform infrared spectrometry. Interestingly, no water was observed penetrating into solvents which are only efficient for EME of nonpolar basic drugs, while water was found to penetrate into the SLM solvents which are efficient for EME of polar basic drugs.