Absorption and emission spectra of four squaraine dyes-bis[4-(dimethylamino)phenyl] squaraine (H-Sq), bis[4-(dimethylamino)-2-hydroxyphenyl]squaraine (HO-Sq), bis(trihydroxyphenyl)squaraine (3HO-Sq), and bis(azulyl)squaraine (Az-Sq)-are reported in dilute films of poly(methylmethacrylate) and polystyrene. Obtained for the first time are the fluorescence Lifetimes of these dyes in these polymer films. Fluorescence lifetimes in liquid solutions are also reported. These emission kinetics combined with measurements of fluorescence quantum yields allow determination of radiative and nonradiative decay rate constants for three of the dyes. Comparison of determined radiative rate constants with those calculated from the absorption spectrum is consistent with the fluorescence originating from the absorbing species and state. The shortest lived fluorescence observed occurs for bis(trihydroxyphenyl)squaraine, and the short lifetime is attributed to either a rapid excited-state proton-transfer tautomerization or deprotonation. The S-1 state of bis(azulyl)squaraine is nonfluorescent, presumably due to a rapid nonradiative decay similar to that which occurs in azulene. However, "S-2" --> S-0 emission is observed for this azulyl-substituted squaraine.