Electronic absorption and fluorescence spectroscopies were used to study the picosecond time scale competition between intersystem crossing and carbon-halogen bond homolysis resulting from 266-nm excitation of 9-chloro- and 9-bromofluorene in the nonpolar solvent cyclohexane. From steady-state fluorescence spectroscopy, fluorescence quantum yields (phi(f)) relative to fluorene (relative phi(f) = 1.0) of 0.036, 0.046, and 0.034 were measured for 2-bromofluorene, 9-chlorofluorene, and 9-bromofluorene, respectively. Picosecond-resolved absorption spectroscopy permitted the detection of S-u <-- S-1 absorption of fluorene near 700 nm which decayed with a time constant of 5.1 ns. Within experimental error, the decay time of this transient absorption band agreed with an observed fluorescence decay time of 5.8 ns for fluorene, thereby providing support for the assignment of this absorption to S-1 of fluorene. From transient absorption measurements, intersystem crossing of 2-bromofluorene occurred with a time constant of similar to 40 ps (k(isc) congruent to 2.5 x 10(10) s(-1)). Excitation of 9-chlorofluorene and 9-bromofluorene resulted in the appearance of absorptions assigned to the 9-fluorenyl radical and to T-1 of the 9-halofluorene. Additional evidence supporting the assignments of absorptions to T-1 of the 9-halofluorenes was provided from transient absorption experiments in which triplet energy transfer was used to populate T-1 of fluorene, 9-chlorofluorene, and 9-bromofluorene. Carbon-halogen bond homolysis does not occur from T-1 for times up to 20 ns postexcitation for these 9-halofluorenes. For 9-chloro- and 9-bromofluorene, intersystem crossing and bond homolysis depopulate S-1. Intersystem crossing in 9-bromofluorene occurs faster than in 9-chlorofluorene [tau(isc) less than or equal to 20 ps (k(isc) greater than or equal to 5.0 x 10(10) s-1) and congruent to 40 ps (k(isc) congruent to 2.5 x 10(10) s(-1)), respectively], resulting in less 9-fluorenyl radical produced via bond homolysis in S-1 from the bromide than from the chloride although the C-Br bond is weaker than the C-Cl bond.