A novel type of heterocycle, viz., 2,3a-disubstituted 5,6-dihydro-3aH-[1,3] oxazolo[3,2-b][1,2,4]oxadiazoles, was generated by an intermolecular Remediated 1,3-dipolar cycloaddition (1,3-DCA) between the oxazoline N-oxide C(Me) ₂CH₂OC(R)=N⁺(O^-) (R = Me, Et) and coordinated nitriles in the complexes trans/cis-[PtCl₂(R′CN) ₂] [R′ = Me, Et, CH₂Ph, Ph, N(C₅H ₁₀)]. The reaction is unknown for free RCN and oxazoline N-oxides, but under Remediated conditions, it proceeds smoothly (CH₂Cl ₂, 20-25°C, 18-20 h) and gives pure complexes [PtCl ₂{N=C(R′)ONC(R)OCH₂CMe₂}₂] [R/R′ = Me/Me, 1; Me/Et, 2; Me/CH₂Ph, 3; Me/Ph, 4; Me/N(C ₅H₁₀), 5; Et/Me, 6; Et/Et, 7; Et/CH₂Ph, 8; Et/Ph, 9; Et/N(C₅H₁₀), 10] in 42-84% yields after column chromatography. Compounds 1-10 were characterized by elemental analyses (C, H, N), FAB⁺-MS, IR, and ¹H and ¹³C{¹H} NMR spectroscopies, and X-ray diffraction (for 1, 2, 5, and 9). With the exception of benzonitrile complexes, 1,3-DCA of oxazoline N-oxides to the Pt^II-ligated nitriles occurred diastereoselectively and afforded mixtures of enantiomers. Depending on the substituents on nitriles, asymmetric atoms in both of the formed heterocyclic ligands have the same (SS/ RR) or different (SR/RS) configurations. The heterocyclic ligands were liberated from 1-4 and 6-9 by treatment with excess ethane-1,2-diamine (en) in CH ₂Cl₂ for 1 day at 20-25°C (for R′ = Me, Et, CH₂Ph) and at 50°C (for R′ = Ph) to achieve the free organic species and the well-known [Pt(en)₂](Cl)₂; the products were separated, and 2,3a-disubstituted 5,6-dihydro-3aH-[1,3]oxazolo[3, 2-b][1,2,4]oxadiazoles (11-18) were characterized by ESI⁺-MS and ¹H and ¹³C{¹H} NMR spectroscopies.