Excited-state dynamics of two novel energetic nitrogen-rich aryl-tetrazole molecules were investigated using femtosecond transient absorption spectroscopy. The internal conversion from Sn to S1 occurred in the 0.3–0.5 ps; vibrational relaxation within S1 states transpired in a 1.8–5 ps time scale and, subsequently, the intersystem crossing was observed with lifetimes of 7.8 ps and 129 ps. The nitro-substituted tetrazole demonstrated a faster decay with a weaker fluorescence compared to the amino-substituted derivative. We believe that the high nitrogen content in the former resulted in a possible more rapid nonradiative decay. © 2021