Spectrophotometric data at near- and mid-infrared (IR) wavelengths are crucial to understand the main evolutionary properties of the Asymptotic Giant Branch (AGB) phase. They can be used to reveal relations between spectral features at near-IR wavelengths and parameters obtained with mid-IR photometric observations (i.e. bolometric luminosity). We are performing such an analysis on a sample of Galactic AGB stars: spectrophotometric data from the IRTS satellite are studied and compared with observations in the mid-IR range obtained by other instruments. In this contribution we present preliminary results for a sub-sample of C-rich sources. We show which spectral features in the 1–4 μm region are most enhanced in the C-rich stars and explore how these features relate with the bolometric stellar luminosity. Finally, we comment on how an Antarctic IR telescope at Dome C will help this research by observations of AGB sources in the Galaxy and in the Magellanic Clouds.