Infrared spectra of Neyveli Lignite samples at different depths from mine cut-I and II were recorded in the region 4000–200 cm−1. Probable assignments of the bands were made with respect to the components present in the samples. The Lignite samples collected at 80m, 82m, 87m and 90m from minecut-I and 52m, 56m and 58m from minecut - II shows distinctly a band at 1500cm−1indicating that these belong to pleistocene—miocene period, while the absence of this band in the samples at deeper depths 92m and 94m from minecut-I and 62m and 65 m from minecut-II indicate that these belong to Oligocene to Palaeocene period.