The optical limiting properties of four optically active phthalocyanine derivatives in chloroform solutions and epoxy resin thin plates were measured at 532 nm with 10 ns pulses. The excited state absorption cross-section sigma (ex) and refractive-index cross-section sigma (r) were determined with the Z-scan technique. These chromophores possess larger sigma (ex) than the ground state absorption cross-section a(0), indicating that they are the potential materials for reverse saturable absorption (RSA). The negative sigma (r) values of these chromophores add to the thermal contribution, producing a larger defocusing effect, which may be helpful in further enhancing their optical limiting performance. The optical limiting responses of the thin plate samples are stronger than those of the chloroform solutions.