This paper presents a combination of in situ synchrotron techniques (diffraction and reflectivity of x-rays) and sheet resistance measurements to study the phase transformations in functional thin films. The association of the three techniques enables simultaneously extracting structural and electrical characteristics of thin films during thermal annealing. For illustrating such combined experiments, two different examples are presented and discussed: the first one deals with solid phase reactions involved in the formation of Ni-based silicides with Pd alloy element, while the second one refers to amorphous-to-crystalline phase transition in chalcogenide materials. For the first case, it is shown that the combined experiments enable measuring the kinetics of Ni-silicide formation by detecting growing and consumed phases (crystallized or amorphous) exhibiting different electrical properties. In the second case, the correlated changes in film density, thickness and sheet resistance are evidenced upon Ge2Sb2Te5 (GST) thin film crystallization. A spread of transition temperature deduced from the different measured parameters is also demonstrated for the thinner GST films. (C) 2012 Elsevier B.V. All rights reserved.