For the first time, predissociated excited electronic states of mixed all;ali trimers exhibiting vibrational structure in their time-resolved spectra were found. The one-color femtosecond pump and probe technique was employed to study the predissociated excited electronic states of Na2K trimer located between 730 and 790 nm. States were populated with one photon of the probe pulse. Dynamics was monitored by ionization of the excited trimer with two photons of the probe pulse. In the case of Na2K, excitation wavelength-dependent dissociation times between 2.5 and 6 ps were obtained. The ion signal of Na2K+ recorded at 770 nm revealed an oscillatory structure with a dominant period of 490 fs, while the transient spectrum of the NaK fragments exhibited oscillations with an estimated period of 440 fs, characteristic for the wave packet dynamics in the NaK A(1) Sigma(+) state. In the case of K2Na, no wave packet dynamics was resolved for the trimer＇s short-living predissociated excited state (tau < 5 ps) populated at 735 nm.