We demonstrate electron and hole-transporting low-voltage transistors based on self-assembling monolayer (SAM) gate dielectrics and solution processed organic small-molecule semiconductors. The studied SAMs include methyl and carboxylic acid terminated molecules. Compared to methyl terminated alkylphosphonic acids, carboxylic acid terminated SAMs are found to exhibit increased surface energy. This enables solution processing of a wide range of small molecules onto the dielectric for the fabrication of low-voltage transistors. Using these transistors we demonstrate complementary inverters operating at voltages⁠. This work is an important step toward realizing low-voltage organic electronics.