A novel discharge configuration has been realized with the XeCl laser IANUS, which has been developed at the ENEA Frascati center as a 1:1 laser head prototype for the 1 kW average output power XeCl system EOLUS (EUREKA EU211 Project). The patented design of the discharge region consists of two active zones which are geometrically in parallel and electrically in series. The obvious advantages of this configuration are, the presence of the intermediate high impedance electrode, suitable for prepulse application, then the absence of current return bars, so improving the recirculating gas flow uniformity, and the automatic synchronization of the two discharges very useful for a compact oscillator-amplifier configuration (POPA). A number of measurements have been done on IANUS, to have an almost complete characterization; based on these results a generalized self-filtering unstable resonator (GSFUR) has been designed and realized on the smaller gap, leaving the other active medium for the high optical quality beam amplification, in the scheme of a POPA system. The GSFUR output beam results are 1.5 times the diffraction limit, with an energy of 9 mJ in a 87 ns FWHM pulse.