In the present work, a new type of semiconducting acetophenone and thiophene side‐arm based polyaryleneethynylene (PAE) conjugated polymers (CPs) were synthesized using the Heck–Sonogashira cross‐coupling reaction. The new type of monomers and APAEC 8 , APAEC 12 , APAEF 8 , TPAEC 8 , TPAEC 12 , and TPAEF 8 (PAE CPs) were synthesized and characterized using Fourier transform IR, NMR and high resolution mass spectrometry studies. The average molecular weight of the CPs was determined using gel permeation chromatography. The data obtained from optical properties in the UV–visible and photoluminescence spectral studies were used to calculate the values of the Stokes shift. Among the six CPs studied, TPAEC 8 was found to possess a lower optical band gap ( E g = 2.112 eV) than those of the other CPs. The data obtained from different studies, it was found that TPAEC 8 exhibits better properties than the other CPs and can be used in the field of organic based photonic, electronic and other sensor applications. © 2020 Society of Chemical Industry