NOVELTY - A conjugated polymer comprises cyclopentadienedithiophene-naphthalene diimide compound (I).    USE - Conjugated polymer for use in organic solar battery apparatus, organic electroluminescence apparatus, and organic field effect transistor (all claimed).    ADVANTAGE - The polymer is prepared by stiller reaction having simple reaction routine, and low process requirement. The polymer has better film forming performance, thermal stability, high current carrier mobility, high molar absorption coefficient and wide light absorption range. The polymer improves matching with sun emission spectrum, and can improve photoelectric conversion efficiency and wide application.    DETAILED DESCRIPTION - A conjugated polymer comprises cyclopentadienedithiophene-naphthalene diimide compound of formula (I).    R 1=1-20C alkyl;    R 2=1-20C alkyl or substituted phenyl moiety of formula (II);    R 3, R 5=1-20C alkyl or alkoxy;    x=1-2;    y=0-1;    x+y=2;and    n=1-120.    INDEPENDENT CLAIMS are also included for the following:    (1) a method for preparing conjugated polymer comprising cyclopentadienedithiophene-naphthalene diimide, which involves using 4,4-dialkyl-2,6-bistrimethyl tincyclopentadiene (2,1-b:3,4b') dithiophene compound of formula (III), 4,4-dialkyl-2,6-dibromocyclopentadiene (2,1-b:3,4b')dithiophene compound of formula (IV) and N,N'-bisubstituted2,6-dibromo-1,4,5,8-naphthalene diimide compound of formula (V) as raw materials, adding the materials and catalyst to organic solvent according to mole ratio, performing stiller reaction for 24-72 hours at temperature of 30-130 degrees C in an anaerobic environment to obtain fluorene copolymer of conjugated polymer containing cyclopentadienedithiophene-naphthalene diimide    (2) an organic solar battery apparatus, which comprises a substrate layer, a electrode layer, an photoactive layer and an another electrode layer. The photoactive layer comprises electron donor material layer and electron acceptor material layer, where the electron donor material layer is made from conjugated polymer containing cyclopentadienedithiophene-naphthalene diimide    (3) an organic electroluminescence apparatus, which comprises a substrate, an anode, a luminescent layer, a buffer layer, and a cathode, where the luminescent layer is made of conjugated polymer containing cyclopentadienedithiophenenaphthalene diimide    (4) an organic field effect transistor, which comprises a silicon substrate, an insulating layer, an organic semiconductor layer, a source electrode and a drain electrode, where the organic semiconductor layer is made from conjugated polymer containing cyclopentadienedithiophene-naphthalene diimide.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating a method for preparing conjugated polymer containing cyclopentadienyl diene dithiophene-naphthalene tetracarboxylic diimide.'(Drawing includes non-English language text)'