  A recent analysis of high angular resolution NIR imaging and spectroscopic
data in conjunction with Plateau de Bure interferometric mm-line observations
indicate the presence of a circum-nuclear starburst ring of about 1.5 arcsec
(1.5 kpc) diameter in I Zw 1. High angular resolution NIR imaging, using the
MPE SHARP camera at the ESO NTT, HST V-band images, as well as NIR spectroscopy
with MPE 3D provide an improved analysis of the star formation activity in the
disk and nucleus of I Zw 1. We present first results from subarcsecond
interferometric imaging in the 12CO(2-1) line using the Plateau de Bure
Interferometer.
