Isatin reacts with N-(2-aminoethyl)-1,3-propanediamine in a 1:1 molar ratio in ethyl alcohol to give new Schiff base, 4-[2-(2-oxoindolin-3-ylideneamino)ethylamino.-3,4-dihydro-2H-pyrido[3,2-b]indole. When the reaction is carried out by fusion, two new Schiff bases, 3-(vinylimino)indolin-2-one and 3-(allylimino)indolin-2-one, are obtained with the liberation of ammonia gas. The synthesis, characterization, and the reactivity of the Schiff bases with mercury(II) acetate and palladium(II) chloride are studied. Elucidation of the structures are based on elemental analyses and infrared (IR), ultraviolet (UV), 1 H-nuclear magnetic resonance (NMR), and mass spectroscopic (MS) spectra.