We have observed the nuclear regions of the galaxies NGC 2146 and IC 342 in 12CO and 13CO J=1−0 and 2−1, as well as CS J=2−1 lines using the FCRAO 14m telescope. The multi-line data are used, in conjunction with radiative transfer model calculations, to estimate the physical conditions of the gas with the purpose of determining the difference between the two galaxies in terms of their gas component. We hope to examine if the gas temperature and column density are dependent on the infrared properties of a galaxy, and whether a warm and optically thin gas component exists in these galaxies, as has been suggested in the case of M82 (Knapp et al.1980), especially for NGC 2146 for which the starburst has been proposed to be a scaled-up version of M82 (Jackson and Ho 1988).