Two-photon induced frequency upconversion emission and two-photon-pumped (TPP) lasing properties of a novel dye, trans-2-[p-(N-ethyl-N-(hydroxyethyl)amino)styryl]-N-methylthiazolinium iodide (1) were investigated. This dye exhibits excellent TPP lasing at similar to577 nm when it is pumped with a 1064 nm pulsed laser beam. The net conversion efficiency from the absorbed 1064 nm pump energy to the similar to577 nm upconverted lasing energy was measured to be similar to2.2%. (C) 2002 Published by Elsevier Science B.V.