The heart of the Laboratory is the modern Bruker ELEXSYS E580 spectrometer for X- and Q- bands (working also in a pulse mode), equipped with helium cryostat and various microwave cavities allowing for measurements of magnetic or electric resonances, as well as changes of electrical resistivity. The recent research activity includes microwave spectroscopy of graphene, topological insulators and polymers applied in active layers of organic solar cells. Quantum transport (weak localization/weak antilocalization effects) observed in graphene allows to study the influence of different factors (e.g. functionalization of graphene) on electron coherence. Electron spin resonance in topological insulators traces properties of free carriers under heavy spin-orbit interactions, as well as magnetic impurity influence on topological properties. Light-induced polaron spin resonance signals in active layers of&npsp;organic solar cells makes it possible to study charge transfer process, the most important phenomenon decisive for the efficiency of photovoltaic cells.