Steady state absorption, fluorescence and femtosecond transient absorption techniques were employed to investigate the excited state relaxation mechanism of trans-ethyl-3-(1H-indole-3-yl)acrylate (trans-EIA). The measured large value of difference in the static dipole moment from ground state to excited state reflects the involvement of excited state intramolecular charge transfer in EIA. The charge-transfer time constant has been estimated to be 0.35 ps. The charge transfer state depletes to the ground state through internal conversion along double bond torsional coordinate at perpendicular conformation with a 1.8 ps time constant, leading to the trans-cis isomerization and was further confirmed by chromatography and H-1 NMR experiments. (C) 2015 Elsevier B.V. All rights reserved.