Cool, luminous stars to probe chemistry & kinematics in dusty-extincted stellar systems

Evolved, cool giants and supergiants are among the brightest stars in any stellar system and are
easily observable out to large distances.
When observed at infrared wavelengths, these cool stars can be also used to probe the stellar content
in environments severely obscured by dust, such as the central regions of galaxies.
Progress in our astrophysical comprehension of the stellar content in such extreme environments
goes together with the technological advance of IR instrumentation.
In this talk I will first present briefly the IR instrument context over the last two decades,
and then I will review some of the most recent results in probing stellar chemistry
and kinematics in the center of the Milky Way and in nearby galaxies.