Abstract. Atoms and Molecules, particularly the latter are known to be sensitive to their physical environs. They have successfully been used to test/refine the available solar model atmospheres. In the present day scenario two sets of models are available viz., three dimensional models and single column homogeneous models. The former group which appears more realistic has led to a substantial reduction in abundances of certain atomic species whereas the latter is simple, easy to use and tested to explain such phenomenon as the C-L variation of continuum fluxes, line profiles of atomic lines, the rotational temperatures of molecular lines, estimates of abundances of several elements and the like. Earlier the lines of the C2 Swan system of bands was utilized by us to determine whether the then available model atmospheres explained the center of the disc and a near limb observation of the rotational temperature. The conclusion was that the center of the disc temperature could well be reproduced but not the near limb one. A suggestion was made to revise the tested model atmospheres in the upper layers. In the nineties when the controversy related to the solar abundance of Iron dominated the scene, after several exhaustive, detailed and careful scrutiny a simple solution was successfully employed to explain away and resolve the apparent controversy. This was related to the separate regions or layers of the solar atmosphere for the formation of lines due to neutral and ionized lines. A model was presented by the Belgian group of solar astronomers. The aim of the present investigation is to report and examine in detail if the model by the Belgian group can reproduce the rotational temperatures of the C2 Swan system of bands and that of the vibration - rotation bands of the CO molecules formed in two very different regions of the photospheric spectrum. A variation on the accepted values of micro-turbulence is also considered. However, it must be noted that no attempt is made to suggest that the simplified and easy to use single column model atmospheres are to be used in place of the three dimensional model again by the Belgian group.