Dimethyl 6‐[1,2‐bis(methoxycarbonyl)‐2‐(triphenyl‐λ5‐phosphanylidene)ethylideneamino]‐2‐methylsulfanyl‐3,4‐pyridinedicarboxylate forms a chain of hydrogen‐bonded rings

In the title compound, C₃₄H₃₁N₂O₈PS, the intramolecular distances provide evidence for polarization of the molecular–electronic structure. The molecules are linked into complex chains of rings by three independent C—H...O hydrogen bonds. The significance of this study lies in its finding that two of the four carbonyl O atoms play no role in the hydrogen bonding, despite the large excess of potential hydrogen‐bond donors present.