LIRIS is a near-infrared (1-2.5 microns) intermediate resolution spectrograph (R=1000-3000) with added capabilities for multi-slit, imaging, coronography, and polarimetry, built by the IAC as a common instrument for the 4.2m WHT (La Palma, Spain). LIRIS has been used as a visiting astronomer instrument at the WHT since summer 2004. The image quality is of 0".5 in the Ks band over the whole field of view (4.2' x 4.2'). Very low values of sky brightness have been measured. Currently, R=1000 is available in the three bands (J, H, Ks), whether R=2500 is only available in the Ks band. R=3000 will be available in the J, H and Ks bands, next year (2007). Here we present some scientific results, as the detection of the CIV 154.9 nm line in the most distant qso at z=6.41.