TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Device: In the device, the material forms a charge transport layer (preferably hole transport layer).    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymer comprises a co-polymer, a homopolymer, and/or a block co-polymer; and is selected from poly(N,N-di(2'-ethylhexyl)-5,11-dihydroindolo(3,2-b)carbazole); poly(N,N'-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)-5,11-dihydroindolo(3,2-b)carbazole); poly(N,N'-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)-5,11-dihydroindolo(3,2-b)carbazole-co-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-phenylene); poly(N,N'-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)-5,11-dihydroindolo(3,2-b)carbazole-co-9,9-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)- fluorene); poly(9,9-bis (2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene); poly(2-(9,9-bis-(2-ethyl-hexyl)-7-methyl-9H-fluoren-2-yl)-6-(9-(2-ethyl-butyl)-9-(2-ethyl-heptyl)-7-methyl-9H-fluoren-2-yl)-benzo(1,2-d;4,5-d')bisoxazole); their conjugates and/or derivatives; where the polymer contains greater than 20 repeating units. Preferred Material: The material further comprises a solvent, and/or a processing aid. Preparation (disclosed): The preparation of the oligomer or the polymer comprising indolocarbazole-based charge transport material selected from monomer compounds (Ia) and (Ib) involves: Yamamoto polymerization that includes adding in Schlenck flask equipped with stirring bar, bis(1,5-cyclooctadiene)-nickel(O), 2,2'-bipyridyl, 1,5-cyclooctadiene and dimethylformamide (DMF); stirring mixture under argon atmosphere at 65 degrees C for 30 minutes and then increasing temperature to 70 degrees C; adding solution of the monomer (Ia) or (Ib) and A'-Aryl-A' in toluene to mixture, and stirring; and adding bromobenzene and stirring to give the oligomer or polymer compound of formula (IIa) or (IIb).n'=3-1000;a and b=not defined;A'=Br, Cl, or I. EXAMPLE - In Schlenck flask equipped with stirring bar was added bis(1,5-cyclooctadiene)-nickel(O) (2.02 equivalents (eq.)), 2,2'-bipyridyl (2.02 eq.), 1,5-cyclooctadiene (2.02 eq.), and dimethylformamide (DMF) ( one quarter of toluene volume). The mixture was stirred under argon atmosphere at 65 degrees C for 30 minutes and then temperature was increased to 70 degrees C. A solution of 2,8-dichloro-6,12-bis-(2-ethyl-hexyl)-6,12-dihydro-6,12-diaza-indeno(1,2-b)fluorene (1 eq., 1/6 M) in toluene was added to mixture, and stirred such as for 16-115 hours. Bromobenzene was then added and reaction mixture was stirred for 1 hour to give poly (N,N'-di(2'-ethylhexyl)-5,11-dihydroindolo(3,2-b)carbazole). The resulting material was light yellow solid (yield = 75%). The electrochemistry of poly(N,N-diethylhexylindolocarbazole) polymer was then determined. The energy levels of highest occupied molecular orbital (HOMO), and lowest unoccupied molecular orbital (LUMO) were estimated to be 5.4 and 2.2 eV, respectively. The HOMO energy level of poly(N,N-diethylhexylindolocarbazole) showed that it was easier to be oxidized i.e. easier hole injection.