The latest generation of infrared spectrometers at medium/high resolution offer a unique opportunity to infer reliable abundances of red giant and supergiant stars. The near IR spectra of these stars are dominated by absorption lines from neutral metals and molecules (CO and OH). I will show a few examples of how these diagnostics are applied to the study of the chemical properties of young stellar clusters and starburst galaxies. Stellar abundances will also be compared to X-ray derived gaseous abundances obtained from high resolution XMM spectra. While metals locked into stars are expected to trace the galaxy metallicity prior to the last burst of star formation, the hot X-ray gas should trace the real-time enrichment by the currently exploding type II SNe.