Novel fully pi -conjugated poly(arylene ethynylene)s 1 and 2 having diphenylmaleimides in the backbone were prepared utilizing a Pd(0)-Cu(I) catalyzed coupling reaction (Sonogashira method) of N-alkyl substituted 1,2-di(4-bromophenyl) maleimides (5 and 6) with 1,4-diethynylbenzene. Whereas polymer 1 with an N-hexyl side chain showed low solubility, 2 having an N-dodecyl group was completely soluble in common organic solvents. Determined by GPC, (M) over bar (w) of 2 was 45800 Da with a polydispersity index of 2.5. Polymer 2 showed UV-visible absorption maxima at 330 nm and 413 nm and greenish yellow fluorescence with a maximum of 530 nm.