Coherent Raman scattering (CRS) microscopy is a label-free method for chemical imaging, as it offers chemical specificity with orders of magnitude better sensitivity than the state-of-the-art confocal Raman scattering microscopy. Currently CRS technique includes coherent anti-Stokes Raman scattering (CARS), and stimulated Raman scattering (SRS). This chapter describes the methods of using CRS microscopy to image major polymers in plant cell wall (i.e., lignin and cellulose). This method can also be used to real-time monitor the chemical processes involved in biomass pretreatment. These together demonstrate CRS as an effective method for imaging complex chemistry in biological systems.