In one example in accordance with the present disclosure a fluid property sensing device is described. The fluid property sensing device includes a substrate having a trench formed therein. The trench includes a bottom surface and opposite side surfaces. A first electrode is disposed on a first side surface of the trench and a second electrode is disposed on a second side surface of the trench. The first electrode and second electrode form a capacitor to measure a complex impedance of a fluid that fills a space between the first electrode and the second electrode. This complex impedance indicates a property of the fluid. A fluid level sensing die, having a number of fluid level sensing components disposed thereon, may be attached to the substrate, preferably in such a way that the fluid level sensing die is surrounded by the trench. In this way the surface area of the electrodes provided in the trench can be increased. The number of level sensing components may be thermal sensing components.