A method for forming a conjugated heteroaromatic polymer is described, wherein at least one compound of formula (1) is polymerized using an acid as a catalyst, wherein X is selected from S, O, Se, Te, PR2 and NR2, Y is hydrogen (H) or a precursor of a good leaving group Y− whose conjugate acid (HY) has a pKa of less than 30, Z is hydrogen (H), silyl, or a good leaving group whose conjugate acid (HY) has a pKa of less than 30, b is 0, 1 or 2, each R1 is a substituent, and the at least one compound of formula (1) being polymerized includes at least one compound of formula (1) with Z═H and Y≠H.