Combined observational data coming from Galaxy Survays, Supernovae and CMB temperature anisotropies show that the Universe is expanding at an accelerating rate. The origing and nature of the energy component driving the current cosmic acceleration is yet uknown. The LCDM model is the simplest model that agrees very well with the data. However, the lack of a theoretical explanation for an almost vanishing cosmological constant has motivated the study of other models, which in general fall into two broad categories of models, namely dynamical dark energy models or geometrical dark energy models. As of now, there are too many models compatible with the current data, as they all predict very similar expansion histories of the universe. Some years ago, two new variables-the statefinders-were introduced, which can discriminate between different dark energy models. In my seminar I shall discuss a geometrical as well as a dynamical dark energy model, and I shall compare two models using the statefinder diagnostics.