IC342 (Distance 4 Mpc) is one of the most suitable sources for extragalactic molecular line studies. Toward its nucleus, a great number of molecular species have been found (see Henkel and Mauersberger, 1990); it is also one of the few galaxies investigated in molecular multi-level studies (Mauersberger and Henkel, 1989). In particular, CO shows strong emission: A 7″ resolution interferometric map of the central parts of this galaxy in the 12CO(1—0) transition by Lo et al. (1984) reveals that the circumnuclear molecular gas is distributed in a bar (size 15″ × 70″) (330 × 1500 pc) extending from the nucleus towards the spiral arms. An interferometric map of the 1—0 line of CO by Ishizuki et al. (1990) shows that the inner part of the bar forms a molecular ring of diameter 110 pc. This inner ring also emits 2 and 6 cm continuum radiation (Turner and Ho, 1983). The kinetic temperature of the denser molecular gas is > 50 K (Martin and Ho, 1986). The H2 density of the gas component seen in CO (Eckart et al., 1990) and CS (Mauersberger and Henkel, 1989) is ∼ 104 cm−3.