We measured the laser-induced fluorescence (LIF) and dispersed fluorescence (DF) spectra of jet-cooled alpha-, o- and in-chlorobenzyl radicals after they were generated by the 193 nm photolysis of the corresponding parent molecules. The vibronically resolved spectra were obtained to analyze their D-1-D-0 transitions. The fluorescence lifetimes of alpha-, o-, m- and p-chlorobenzyls in the zeroth vibrational levels of the D-1 states were measured to estimate the oscillator strengths of a series of benzyl derivatives. It was found that the alpha-substitution is inefficient to break the 'accidental forbiddenness' of the D-1-D-0 transition of benzyl, while the ring-substitution enhances the oscillator strength by 50%. (C) 2002 Elsevier Science B.V. All rights reserved.