A porphyrin-fullerene covalently linked dyad is studied in solutions and Langmuir-Blodgett (LB) films. The dyad is characterized by a relatively long linker. In benzonitrile, it performs a relatively slow photo-induced electron transfer (ET), kET ≈ 5 × 108 s-1. Being incorporated in an LB film the dyad forms a compact conformer, which takes the smallest surface area. For this conformer the donor-acceptor separation is much shorter as compared with that in liquid phases and the molecule perform a fast photo-induced ET, kET ≈ 8 × 109 s-1. The LB films were studied using time-resolved measurements of fluorescence, absorption, and Maxwell displacement charge.