This paper presents an alternative approach to obtain, from experimental measurements, physical parameters of organic solar cells associated with a given model. In order to get rid of the limitations of common fitting methods, we use a specific Markov chain Monte Carlo technique. This method is applied to a two-dimensional model of an organic solar cell. Measurements carried out under dark and one sun conditions, from two complementary cells, allow access to more reliable values of the active layer parameters. The corresponding set of parameters generates JV -curves in excellent agreement with the measurements for a range of different illumination intensities. Similar extractions are applied on temperature-dependent parameters, from experimental data acquired at various temperatures. As the simulation results reproduce the measurement data rather well, we show that this approach can also be useful to test or determine the governing law associated with some of the temperature-dependent parameters. In addition, analyzing the simulated responses of the model allows the identification of model limitations. The approach discussed in this paper, not specific to organic solar cells, can be applied to a large range of condensed matter topics.