A soluble phthalocyanine derivative, tetra-α-(2-ethylbutoxyl)chloro-indium phthalocyanine, has been synthesized through the corresponding metal-free phthalocyanine. The optical limiting properties of its THF solution were investigated by a 7 ns pulses laser at 532 nm. It was found that the compound exhibited good optical limiting performance. With a very low input fluence, the output fluence roughly obeyed Beer's law, and the transmittance decreased very quickly with the increase of the input fluence. The...