  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 been 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.
