Abstract <p>The synthetic potential of the imine version of the Pudovik reaction was significantly enhanced by studying the reaction of dialkyl phosphites (DAPh), dialkyldithiophosphoric acids, and diphenyl- and diethyldithiophosphinic acids with aldimines containing halo- and dihalo-substituted aldehyde moiety: new types of phosphorus compounds have been designed and the reactions, previously undescribed in the literature, have been discovered. The 2-chloralkyl radical at P(IV) in the addition products of DAPh to <i>N</i>-alkyl-2-chloraldimines is isomerized into a 1-chloroalkyl radical through the intermediate aziridinium salt. This salt is converted into phosphorus-containing aziridine and alkyl-2-(dialkoxyphosphoryl-1,1-dimethyl-2-chloroethyl)ammonium chloride. The latter with methoxy groups at P(IV) is transformed into betaine, alkyl(2-methoxyphosphonato-1,1-dialkyl-2-chloroethyl)ammonium. <i>N</i>-alkyl-2-bromoaldimine reacts with DAPh to release methyl bromide and to form a compound with a completely different structure: 2-methoxyphosphonatoaziridinium. The above-mentioned new types of organic phosphorus compounds were synthesized by the discovered new reactions of DAPh with <i>N</i>-alkyl-2-haloaldimines. In the reaction of <i>N</i>-alkyl-2-chloro- and bromoaldimines with <i>O</i>,<i>O</i>-dialkyldithiophosphoric and diphenyl- and diethyldithiophosphinic acids, the imine nitrogen atom is first reversibly protonated to form the initial intermediate iminium salt. The further transformation of this salt depends on the nature of the halogen, the dithioacid structure, and the ratio of the reagents. Three new reactions of phosphorus dithioacids with <i>N</i>-alkyl-2-halo- and 2,2-dihaloaldimines were discovered: (1) with <i>N</i>-alkyl-2-chloroaldimines in a 1 : 1 ratio, where the initial iminium salt is transformed into a new iminium salt, <i>N</i>‑alkyl-2-(dialkoxythiophosphorylthio)aldiminium chloride, via the nucleophilic substitution of the chlorine atom by <i>O</i>,<i>O</i>-dialkylthiophosphorylthio group in a labile addition product. When the initial ratio is 1 : 2, a new reaction route is implemented in parallel—the reduction of the initially formed iminium salt at the C‒Hlg bond (C‒Cl → C‒H). In the reaction of 2-chloroaldimines with diphenyl- and diethyldithiophosphinic acids, which are weaker than dithiophosphoric acids, both routes are realized: nucleophilic substitution and reduction. The contribution of each route depends on the acid strength and the ratio of reactants. In the case of diphenyldithiophosphinic acid, at an acid: imine ratio of 1 : 3, substitution prevails; (2) with <i>N</i>-alkyl-2-bromaldimines in ratios 1 : 1 and 2 : 1, where a dithioacid participates in the reduction of the primary iminium salt cation on the C–Br bond (C‒Br → C–H). The second reaction product is bis(dialkoxythiophosphorylthio)disulfide. The occurrence of reduction through the enamine intermediate is experimentally confirmed by the implementation of a sequential three-component interaction “dithioacid + enamine + sulfenyl bromide,” which results in the formation of an iminium salt reduced at the C‒Br bond and a diphosphorylated disulfide; (3) with N-alkyl-2,2-dihalaldimines, where the cation of the initially formed iminium salt is reduced at the C–Hlg bond (C–Hlg → C–H) into 2-haloaldiminium halide, regardless of the nature of the halogen (Cl or Br). The final iminium salt—<i>N</i>-<i>tert</i>-butyl-2-(isopropoxythiophosphorylthio)propaniminium halide, is formed as through nucleophilic substitution of the halogen atom in the reduced iminium salt.</p>