Top-contact and bottom-gate thin-film transistors (TFTs) were fabricated employing polycrystalline SnO films as the channels. The influence of channel thickness, source/drain electrode materials with different work function and post-annealing of the devices on the electrical properties of the TFTs was systematically investigated. Ambipolar TFTs which possesses balanced electron and hole field-effect mobilities were achieved. Complementary metal oxide semiconductor (CMOS) - like inverters using the SnO dual operation transistors were also demonstrated with a gain up to 30. These results also demonstrate that, a simple route in realizing oxide-based ambipolar TFTs and CMOS-like inverters, provides a robust addition to the existing CMOS technology community.