The final phase of a star's life is crucial for the understanding of the chemical evolution of our Galaxy. The planetary nebula phase offers an excellent opportunity to study the nucleosynthesis history of low– and intermediate-mass stars, and to study the evolution of dust in evolved objects. For these purposes, infrared spectroscopy has been an ideal method to both determine accurate abundances and characterize the dust features that are seen in their spectra. This contribution briefly summarizes some of the main infrared spectroscopic advances in the field during the last few years, with emphasis on the recent results/projects from the Spitzer Space Telescope on galactic and extra–galactic planetary nebulae.