AbstractReactions of the three phospholes 1‐phenylphosphole, 3‐methyl‐1‐phenylphosphole and 3,4‐dimethyl‐1‐phenylphosphole with dimethyl acetylenedicarboxylate are reported. All three phospholes react extremely readily with the acetylenic ester to give ring‐expanded bicyclic ylidic systems, although 1‐phenylphosphole appears to react by a different pathway from the other two phospholes. These reactions show that simple phospholes in general, in contrast to heavily substituted phospholes, are quite good nucleophiles in organic reactions and the results of this study are consistent with a relatively easily perturbed aromatic structure for