NOVELTY - A pentacene or tetracene derivative is new.    USE - The pentacene or tetracene is used for the formation of conductive thin films for electrically conductive assemblies such as semiconductors or photovoltaic devices.    ADVANTAGE - The pentacene or tetracene uses precursor that has improved solubility in various organic solvents and has good charge mobility. The pentacene or tetracene can be produced at very high purity thus providing high purity pentacene films in organic thin film transistor.    DETAILED DESCRIPTION - A pentacene derivative of formula (A) or (B); or tetracene derivative of formula (C) is new.    R1-R8=H, Me, CN, OCH3, Ph, F, Cl, and/or Br;    R9=H or trimethyl silyl alkynyl group;    X1-X5=presence or absence of carbonyl bridge;and    Y'=presence or absence of ketal bridge.    Provided that one or more of X1-X5 is carbonyl bridge; when the carbonyl bridge is absent the corresponding six-member ring is aromatic; and when X3 is a carbonyl bridge, one or more of X1-X5 is a carbonyl bridge or R1-R9 are not all hydrogen. Provided that one or more of Y'in formula (B) is ketal bridge, and when the ketal bridge of (-OC(R10R11)C(R12R13)O) is absent the corresponding six-membered ring is aromatic.    R10-R13=H, or CH3;    R10=CH2CH2CH2CH2CH3, Ph, CH=CH-CH=CH;    R10-R11=C2H6, CH2CH2CH2CH3, CH=CH;or    R11=CH2CH2CH3.    INDEPENDENT CLAIMS are included for:    (1) forming film on substrate comprising applying composition containing pentacene derivative to form a film on the substrate, and expelling volatile units of carbon monoxide or carbon dioxide from film by thermally treating of film or photochemically treating the film; and    (2) anthracene derivative of formula (D).    R14=Ph, toluenyl, cyano phenyl, trifluoromethyl phenyl, thiophene ethylenyl, phenyl ethylenyl, methyl phenyl ethylenyl, cyano phenyl ethylenyl, m-thiophene ethylenyl, trifluoromethyl phenyl ethylenyl, nitro phenyl, nitrophenyl ethylenyl, pentafluoro phenyl, pentafluorophenyl ethylenyl, or preferably thionyl, thiophene propynyl, phenyl, or propynyl phenyl.