Vectorial electron transfer occurs in Langmuir-Blodgett films when semiamphiphilic porphyrin-phthalocyanine dimers are photoexcited with ultrashort laser pulses. The primary charge carriers are generated from the singlet excited states of the donor-acceptor pairs while the secondary charge carriers are issued from cascade reactions involving the triplet excited state of the dimer. Their quantum yield and lifetime are measured.