A systematic study of the behaviour of aryl γ-halopropargyl ethers under thermal condition was undertaken. Aryl γ-bromopropargyl ethers 2 underwent unique transformation in N,N-diethylanillne (215°C, 6 h) giving rise to a mixture of products 3,4and 5, whereas, under similar conditions aryl γ-chloropropargyl ethers ulbar|8, afforded 4-chlorochromenes, 9. A remarkable substituent and solvent effect has been observed in the thermolysis of these aryl γ-bromo and γ-chloropropargyl ethers, rendering this transformation as a method for the synthesis of a number of substit uted 4-bromochromenes 3, 4-chlorochromenes 9 and chroman-4-ones 7. In contrast, solution thermolysis of aryl γ-iodopropargyl ether 11 afforded aryl propargyl ether 1 as the major product. © 1989.