NOVELTY - An adduct compound having structure formed by disconnectably adding a compound (c1) having double bond to a condensed polycyclic aromatic compound (I), is new.    USE - New adduct compound is used for solution for forming organic-semiconductor film used for manufacturing organic-semiconductor device e.g. thin-film transistor (all claimed), and solar cell.    ADVANTAGE - The lightweight organic-semiconductor device is economically manufactured, using the adduct compound.    DETAILED DESCRIPTION - An adduct compound having structure formed by disconnectably adding a compound (c1) having double bond to a condensed polycyclic aromatic compound of formula: Ar1Ar2Ar3 (I), is new.    Ar1,Ar3=optionally substituted fused aromatic-ring portion having condensed 2-5 aromatic rings;    Ar2=optionally substituted aromatic-ring portion or optionally substituted fused aromatic-ring portion having condensed 2-5 aromatic rings;and    or Ar1+Ar2,Ar2+Ar3=fused aromatic ring.    INDEPENDENT CLAIMS are included for the following:    (1) adduct compound-containing solution, which is obtained by dissolving adduct compound in a solvent;    (2) production of organic-semiconductor film, which involves coating adduct compound-containing solution or ( alpha )-diketone compound of formula: Ar10Ar11Ar12 (XXX) to a base material to form a film, and exposing film to pressure reduction and/or heating;    (3) manufacture of organic-semiconductor device (10);    (4) organic-semiconductor device, which has a source electrode (2), a drain electrode (3), a gate electrode (7), a gate insulating film, and organic-semiconductor film. The source electrode, drain electrode and gate electrode are insulated by gate insulating film. The electric current which flows to drain electrode through organic semiconductor (1) from source electrode with voltage applied to the gate electrode is controlled;    (5) synthesis of organic compound, which involves mixing condensed polycyclic aromatic compound (I) with compound (c1);    (6) purification of condensed polycyclic aromatic compound (I), which involves disconnectably adding compound (c1) to crude product of condensed polycyclic aromatic compound (I), mixing and dissolving condensed polycyclic aromatic compound (I) and compound (c1) to obtain liquid mixture, separating and purifying condensed polycyclic aromatic compound (I) from liquid mixture;    (7) manufacture of adduct compound;    (8) manufacture of condensed polycyclic aromatic compound (I), which involves purifying crude product of condensed polycyclic aromatic compound (I);    (9) ( alpha )-diketone compound (XXX);    (10) ( alpha )-diketone compound-containing solution, which is obtained by dissolving ( alpha )-diketone compound (XXX) in organic solvent; and    (11) synthesis of ( alpha )-diketone compound (XXX), which involves hydrolyzing vinylene carbonate addition-condensed polycyclic aromatic compound having structure formed by disconnectably adding vinylene carbonate to condensed polycyclic aromatic compound (I) to obtain ( alpha )-diol compound, oxidizing ( alpha )-diol compound and converting ( alpha )-diol portion to ( alpha )-diketone portion.    Ar10,Ar12=optionally substituted fused-aromatic-ring portion having condensed 2-5 aromatic rings, where at least one of aromatic ring is substituted by bicyclo(2.2.2)octa-5,7-diene-2,3-dione, preferably groups chosen from formulae (v)-(viii);    Ar11=hetero aromatic ring portion comprising one hetero aromatic ring, or condensed hetero aromatic ring portion having condensed 2-5 hetero aromatic rings (both optionally substituted), preferably optionally substituted group of formula (i), (iii) or (iv);and    or Ar10+Ar11,Ar11+Ar12=condensed ring.    (i) The condensed benzene ring portion of ( alpha )-diketone compound (XXX) is optionally substituted by halo, 1-20C alkyl, 2-20C alkenyl, 2-20C alkynyl, optionally substituted 4-20C aromatic group, 2-10C ester, 1-20C ether, 1-20C ketone, 1-20C amino, 1-20C amide, 1-20C imide or 1-20C sulfide.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the thin-film transistor.    Organic semiconductor (1)    Source electrode (2)    Drain electrode (3)    Gate electrode (7)    Organic-semiconductor device (10)