Abstract: An acyclic enediyne with maleimide as the main structure and two symmetrical alkynyl chains was synthesized through Sonogashira coupling reaction.The enediyne was subjected to thermal Bergman cyclization to yield diradical intermediates.FT-IR results showed the complete conversion of the alkynyl moiety.The diradical intermediates could be further trapped by a spin trap (PBN) to generate mono-and di-PBN adducts corroborating the occurrence of the Bergman cyclization,which was confirmed by EPR analysis.MTT cell activity experiments confirmed that the half inhibitory concentration of this small molecular enediyne on tumor cell was around 18 μmol/L which were stable enough for long-time storage and active enough to suppress the cell multiplication for potential clinical application.