The electronic absorption and emission spectra of perylene (C20H12) isolated in rare gas (Ne, Ar) and N-2 matrices are presented. While the electronic band systems show, in all matrices, the same fundamental frequencies as those observed in gas-phase jet experiments, the spectra in Ar and N-2 matrices exhibit much more spectral structure. The observed structure points to strong host-guest interactions and provides new insight into the low frequency modes of perylene. In particular, the spacing observed at 11 and 16 cm(-1) in the S-0 and S-1 states, respectively, might be attributed to the gerade accordion mode of perylene. This mode, which has never been observed directly in jet experiments, could be induced into activity in solid matrices.