UV photoexcitation of trans-(η4-BDA)Fe(CO)3 (1) in alkane solvent generated a short-lived isomeric species whose identity was confirmed by infrared spectroscopy and supported by DFT calculations. This intermediate (2) exhibits an unusual ɳ2 coordination of the benzyl group to a vacant site on the iron center and is computed to be 7.8 kcal/mol less stable than 1. While thermal substitution of the BDA ligand from 1 by phosphites was found to be very slow at room temperature, photolysis of 1 in the presence of P(OEt)3 results in BDA displacement from 2 within seconds. Intermediate 2 may be of relevance in the previously reported photocatalyic dehydrogenation of formic acid by 1.