In this work, nanosecond laser ablation plasmas generated at 266 and 1064 nm of the two pyrimidine nucleobases uracil and thymine were characterized using time-of-flight mass spectrometry, optical emission spectroscopy and temporally resolved third harmonic generation of a probe laser. This multiple technique approach provides insight into the role played by the irradiation wavelength on the composition and dynamics of plasma species and on the differences between the laser plasmas of the two nucleobases. (C) 2013 Elsevier B.V. All rights reserved.