We present examples of an extended asteroseismic modelling in which we aim at fitting not only pulsational frequencies but also certain complex parameter related to each frequency. This kind of studies, called textbf{complex asteroseismology}, has be
en successfully applied to a few main sequence B-type pulsators and provided, in particular, plausible constraints on textbf{stellar opacities}. Here, we briefly describe our results for three early B-type stars.
