Monoclinic thin films of PbPc were deposited on KBr disc substrates by a high-vacuum thermal-evaporation technique. The infrared response of the films was studied with respect to chlorine and iodine exposure in the range 400-4000 cm-1. Doping with chlorine and iodine led to a generation of acceptor levels within the band gap and led to a splitting of the valence band. The data was analysed to estimate the intraband transition energy between the valence subbands. The ionization energy of the acceptor levels was estimated.