New soluble Zn phthalocyanine substituted by 3-diethylamino-1-propylsulphona-mide groups, as potential material for photodetectors is presented. Optical absorption spectrum consists of two strong Q and floret bands with maxima at 680 and 338nm, respectively. HOMO and LUMO energies of thin film were determined by electrochemical method to be approximately 5.8 and 4.1 eV, respectively. The material under study is strongly photoconductive; the photoconductivity spectrum is symbatic with optical absorption. Current-voltage characteristics show ohmic behavior at low electric fields (F < 10(6)V m(-1)); a strong hole injection from electrode was observed at higher fields.