subsequently reacting the reaction product with a monoazo compound represented by formula vi shown above a metalizable azo compound represented by formula iv shown above can be obtained by coupling the diazonium salt of o m or p aminobenzenephosphonic acid with an aniline or aminobenzene derivative having substituents x and r 9 x and r 9 have the same definitions as above to yield a monoazo compound represented by formula xi str13 wherein ps x and r 9 have the same definitions as above and subsequently reacting the diazonium salt of the monoazo compound with a coupler that forms a coupling component residue d d has the same definition as above examples of compounds selected as appropriate for the production of azo compounds of formulas i through iv shown above the aminobenzenephosphonic acid may be o m or p aminobenzenephosphonic acid with preference given to m or p aminobenzenephosphonic acid examples of benzidine derivatives include 3 3 39 dihydroxybenzidine 3 3 39 dimethoxybenzidine 3 3 39 diethoxybenzidine 3 3 39 dicarboxybenzidine and 3 3 39 dimethylbenzidine examples of the coupling component that forms formula v include h acid s acid and k acid examples of the coupling component that forms formula ix include h acid s acid and k acid examples of the coupler that forms a include m hydroxybenzoic acid m aminophenol m phenylenediamine pyrocatechol salicylic acid h acid s acid k acid m acid chromotropic acid j acid 2r acid r acid nw acid and schaffer 39 s acid examples of the coupler that forms the coupling component residue d hereinafter referred to as coupler d include.