Crystalline brominated poly-1,6-di-(N-carbazolyl)-2,4-hexadiyne having at least two bromine atoms per repeat unit is disclosed. The crystalline brominated poly-1,6-di-(N-carbazolyl)-2,4-hexadiyne of the invention is characterized by a Fourier transform infrared spectrum which includes absorption at 795.+-.5, 835.+-.5, and 865.+-.5 cm.sup.-1. A method for preparing the crystalline brominated poly-1,6-di-(N-carbazolyl)-2,4-hexadiyne of the invention is also disclosed.