A bichromophoric compound, 3beta-((2-(methoxycarbonyl)quadricyclane-3-yl)carboxy)androst-5-en-17beta-yl-{3,3-dibenzoylmethanatoboron difluoride} propionate (QC-S-BF2) was synthesized, and its photochemistry was examined using both steady-state and time-resolved techniques. Fluorescence quenching and lifetime measurements indicate that intramolecular electron transfer from the QC group to the singlet excited state of the BF2 chromophore in QC-S-BF2 occurs with efficiency of ca. 25% and rate constant of ca. 1.0 x 10(9) s(-1). Selective excitation of the BF2 chromophore results in the valence isomerization of the quadricyclane group to norbornadiene group with quantum yield of ca. 5.8%.