The　photophysical　properties,　such　as　the　UV-vis　absorption　spectra,　triplet　transient　difference　absorption　spectra,　triplet　excited-state　extinction　coefficients,　quantum　yields　of　the　triplet　excited　state,　and　lifetimes　of　the　triplet　excited　state,　of　10　novel　zinc　phthalocyanine　derivatives　with　mono-　or　tetraperipheral　substituents　have　been　systematically　investigated　in　DMSO　solution.　All　these　complexes　exhibit　a　wide　optical　window　in　the　visible　spectral　range　and　display　long　triplet　excited-state　lifetimes　(140-240　μs).　It　has　been　found　that　the　complexes　with　tetrasubstituents　at　the　a-positions　exhibit　a　bathochromic　shift　in　their　UV-vis　absorption　spectra,　fluorescence　spectra,　and　triplet　transient　difference　absorption　spectra　and　have　larger　triplet　excited-state　absorption　coefficients.　The　nonlinear　absorption　of　these　complexes　has　been　investigated　using　the　Z-scan　technique.　It　is　revealed　that　all　complexes　exhibit　a　strong　reverse　saturable　absorption　at　532　nm　for　nanosecond　and　picosecond　laser　pulses.　The　excited-state　absorption　cross　sections　were　determined　through　a　theoretical　fitting　of　the　experimental　data　using　a　five-band　model.　The　complexes　with　tetrasubstituents　at　the　a-positions　exhibit　larger　ratios　of　triplet　excited-state　absorption　to　ground-state　absorption　cross　sections　(σT/σg)　than　the　other　complexes.　In　addition,　the　wavelength-dependent　nonlinear　absorption　of　these　complexes　was　studied　in　the　range　of　470-550　nm　with　picosecond　laser　pulses.　All　complexes　exhibit　reverse　saturable　absorption　in　a　broad　visible　spectral　range　for　picosecond　laser　pulses.　Finally,　the　nonlinear　transmission　behavior　of　these　complexes　for　nanosecond　laser　pulses　was　demonstrated　at　532　nm.　All　complexes,　and　especially　the　four　a-tetrasubstituted　complexes,　exhibit　stronger　reverse　saturable　absorption　than　unsubstituted　zinc　phthalocyanines　due　to　the　larger　ratio　of　their　excited-state　absorption　cross　sections　to　their　respective　ground-state　absorption　cross　sections.　©　2008　American　Chemical　Society.