A new grating (JS50XL) for ultrasoft-X-ray spectroscopy in an energy range 50–200 eV was designed, manufactured and tested. A spectrometer composed of the grating and a multi-channel plate detector was constructed. At the low-energy end of this spectrometer, a sharp Fermi edge of Mg-L emission was observed at 49.5 eV with an energy resolution of 0.15 eV. Li-K emission spectra were obtained from metal-Li, surface-oxidized metal-Li and 5% Li–Al. Relative energy shifts observed in Al-L emission spectra of Al, AlN and MgAl₂O₄ were explained by shifts in core binding energies (chemical shift) and bandgap energies of those materials. Si-L emissions from Si, SiC and SiO₂ (quartz) and P-L emissions from GaP and InP were presented. Furthermore, the grating was tilted to extend the lower limit of detection energy to 32 eV, and the whole intensity distribution of Mg-L emission was successfully obtained. These ultrasoft-X-ray emission spectra show a successful extension to lower-energy range using the new soft-X-ray emission spectroscopy instrument in electron microscopy.