NOVELTY - Making a phosphono-substituted dipyrromethane, comprises reacting an aldehyde or acetal having at least one phosphono group substituted on it with pyrrole to produce a phosphono-substituted dipyrromethane, where the phosphono is dialkyl phosphono, diaryl phosphono or dialkylaryl phosphono.    USE - The method is useful for making phosphono-substituted dipyrromethane, porphyrin substituted, substituted porphyrin compound, phosphonoic acid-substituted porphyrin or chlorine (all claimed), where the phosphono-substituted dipyrromethane compound is useful for the production of solar cells and molecular memory devices, and as light harvesting rods, light harvesting arrays and information storage molecule.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) making a porphyrin substituted at the 5 position with the phosphono group, comprising reacting a 5-phosphono-substituted dipyrromethane with a dipyrromethane-dicarbinol to produce the porphyrin;    (2) a porphyrin substituted at the 5th and 10th position with a phosphono group;    (3) making a substituted porphyrin compound, comprising reacting a halo-substituted porphyrin with a phosphite or its salt to produce a porphyrin having a phosphono group coupled to it, where the phosphite is dialkyl phosphite, diaryl phosphite, dialkylaryl phosphite, trialkyl phosphite, triaryl phosphite or trialkylaryl phosphite;    (4) a method-1 of making a phosphonoic acid-substituted porphyrin or chlorine, comprising reacting a porphyrin or chlorine having a protected phosphono group substituted on it at the 5 position with a trialkylsilyl halide and a base in a solvent to produce a porphyrin or chlorine having a phosphonic acid group substituted on it; and    (5) a method-2 of making coupled porphyrins, comprising reacting nitrogen a first porphyrin substituted with a halo or ethyne group and a protected phosphono group with (ii) a second porphyrin having an ethyne or halo group in a Sonogashira reaction to couple the first and second porphyrins, where the first porphyrin is substituted with halo when the second porphyrin is substituted with ethyne, and the first porphyrin is substituted with ethyne when the second porphyrin is substituted with halo.