Dependencies of photoluminescence in five membered heterocyclic conducting polymers on heteroatoms and temperature are studied. Luminescence intensity of poly(3‐alkylthiophene)s increases with temperature and luminescence intensity of poly(3‐alkylfuran)s is slightly enhanced with increasing temperature. However, luminescence intensity of poly(3‐hexylselenophene) is even suppressed with temperature. These difference of properties among heterocyclic conducting polymers with different heteroatoms can be interpreted in terms of the difference of steric hindrance effect between heteroatoms and alkyl side chain and the interchain interaction which influence on the dynamics of excited species and recombination.