In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants during an instrument intercomparison campaign (CINDI-2) at Cabauw, the Netherlands. Here we report on the outcome of this intercomparison exercise. The three major goals were to characterize the differences between the participating instruments, to define a robust methodology for performance assessment, and to contribute to the harmonization of the measurement settings and retrieval methods.