NOVELTY - The photofunctional material (1) having vinylidene phosphonic acid group is new.    USE - For use in photoelectric conversion material, which is used for photoelectric conversion electrode used in photoelectric conversion cell (all claimed). The photofunctional material is also used as luminescent material, optical recording material, image forming material, photochromic material, electroluminescent material, photoconductive material, dichromatism material, radical generating material, acid generating material, base generating material, luminous material, non-linear optical material, second harmonic generation material, third harmonic generation material, photosensitive material, optical absorption material, near infrared absorption material, photochemical hole burning material, light sensing material, light marking material, sensitizing material for photochemical treatment, light phase transition recording material, light sintering recording material, magneto optical recording material and pigment for photodynamic therapy.    ADVANTAGE - The sensitizing dye has high photoelectric conversion efficiency and strong adsorption to interface of inorganic semiconductor. The photofunctional material has sensitizing effect, heat generation effect, color development effect, discoloring effect, luminous effect, phase transition effect, photoelectric conversion effect, magneto optical effect, photocatalyst effect, light modulation effect, light recording effect and radical generation effect. The sensitizing dye is eco-friendly, since water is used as solvent. The material has photoelectric conversion function over broad wavelength region with respect to sunlight, since another photoelectric conversion material is combined with the sensitizing dye.    DETAILED DESCRIPTION - The photofunctional material of general formula (1) having vinylidene phosphonic acid group is new.    X = univalent organic residue;    R1,R2 = H, univalent organic residue or electron attractive group;    M1,M2 = H, (un)substituted alkyl, aryl, silyl or positive ion, and R1 and R2, R1 and X, and R2 and X optionally combine with each other to form a ring.    INDEPENDENT CLAIMS are included for the following:    (1) sensitizing dye containing light functional material;    (2) photoelectric conversion material which contains an inorganic semiconductor and sensitizing dye connected to the inorganic semiconductor;    (3) photoelectric conversion electrode which contains a transparent electrode and photoelectric conversion material laminated on transparent electrode; and    (4) photoelectric conversion cell containing photoelectric conversion electrode, electrolyte layer and electroconductive counter electrode.    DESCRIPTION OF DRAWING(S) - The figure shows the sectional drawing of the test sample as example of photoelectric conversion cell.    Electrolytic solution layer (2)    Fluorine doped type tin oxide layer (32)    Glass substrate (51,52)    Spacer (61,62)    Conductive wire (71,72)