The triclinic NbSe 2 I 2 has a van der Waals layered structure, so it should be exfoliable down to few layer flakes. We mechanically exfoliated NbSe 2 I 2 single crystals with the established Scotch tape method onto a 285 nm thick SiO x on Si wafer, and obtained flakes down to few-layer and mono-layer thickness. Figure (a) shows optical microscope images of the resulting exfoliated NbSe 2 I 2 . Due to thin film interferometry, the changes in color correspond with changes in thickness of the film. The SiO x on Si substrate is brown/tan (with different color in the different images due to changes in illumination levels), the monolayer crystal appears as a light, translucent purple color while the few-layer crystal has a darker, opaque purple color, and the the bulk crystals are light blue. Raman spectroscopy probes the phonon transitions in 2D materials, making it a quick, non-destructive method to identify many structural and electronic properties such as layer number, lattice symmetry, edge termination, strain, doping, defects, and magnetic order. Figure (b) shows the Raman spectrum of the bulk (more than 20 layers), few-layer and monolayer crystals. The Raman modes for the bulk and few-layer crystals match well, with only a difference in intensity, suggesting the preservation of the crystal structure and the electronic levels after exfoliation. In contrast, the Raman spectrum of the monolayer flake shows weak to no signal compared with that from thicker samples. We attribute this to two possible scenarios. First, many 2D van der Waals materials are reactive to air, with the outer layers oxidizing, thus making monolayers unstable. Second, even if the crystal is stable, it may degraded due to thermal effects during the intense laser excitation of Raman spectroscopy. Next, in Figure (c), we performed polarized Raman spectroscopy to probe the crystal structure. The two spectra show the response for excitation polarized along < ZXX Z > and perpendicular to < ZY Y Z > the horizontal X axis, which we align to the long, cleaved edge of the few-layer sample in Figure . In particular, during exfoliation, van der Waals crystals tend to cleave along the low-symmetry axis, which we assume to be oriented along the a axis. The two spectra show that some of the Raman modes exist at both polarizations, while other modes only exist at one polarization. This behavior is similar to what is observed in other 2D materials with lower symmetry, and can be used as a method for identifying lattice orientation. Finally, in addition to the Raman spectroscopy, photoluminescence (PL) spectroscopy was performed to probe the optical transitions. Shown in Figure , 39 there were no distinct peaks observed, suggesting the material has an indirect band gap, which we show here subsequently.