2-Bromothiophene was prepared according to an earlier description3, the sodium acetylide by known methods28., and the 2-chlorothiophene used was a commercial product. While 2-chlorothiophene did not react and the starting material was recovered quantitatively, 2-bromothiophene reacted vigorously. To the prepared sodium acetylide in liquid ammonia the calculated amount of 2-bromothiophene was added by drops. The reaction mixture was stirred for four hours and hydrolysed with water. When sodium acetylide was prepared without using a catalyst (hydrated iron nitrate), the reaction mixture turned from colourless to light brown and finally, after hydrolysis of the mixture, to black. There was also present a~ large amount of free carbon. Under analogous conditions, when employing 2-chlorothiophene, no free carbon was noticed. After isolation of the reaction product with ether, there resulted a crystalline substance and we regained some starting material. From 50 gm. (0-32 mole) of 2-bromothiophene we obtained 10-14 gm. of the crystalline substance, 13 gm. (0-08 mole) of recovered 2-bromothiophene, and 2 gm. of a high-boiling oil, probably a mixture of di- and tri-bromothiophene. The yield of the crystalline substance was 35-45 per cent, depending on the method of preparation of the sodium acetylide. The yield was greater when the sodium acetylide was prepared via sodium amide using an iron nitrate catalyst.The substance, recrystallized from dilute ethanol, gave white needles melting at 114 C. The analysis gave the following results : calculated for C4Br4S : C, 12-02; Br, 80-00; S, 8-04; found: C, 12-31; Br, 80-25 ; S, 8-44. The molecular weight determined by the Rast method was 38012. The product was identified as tetrabromothiophene, in that it did not depress the melting point on admixture with an authentic specimen prepared according to the method of Volhard and Erdmann4. Further investigations on this type of reaction are being carried out.