We report emission from a series of aryl substituted polyacetylenes poly(phenylacetylene) (PPA), poly(p-ethynyl phenylacetylene) (PEPA), poly(p-phenylethynylphenylacetylene) (PPEPA), and poly[p-(2-thiophenylethynyl)phenylacetylene (PTEPA). These polymers are readily soluble, easily processable from organic solvents, and stable up to 200 degrees C either in air or in nitrogen according to thermogravimetric analysis. Single layer light-emitting diodes using PPA, PEPA, PPEPA, and PTEPA as an emissive layer were fabricated. The effects of substituted groups on W-vis absorption, photoluminescence and electroluminescence spectra of the polymers are discussed.