TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compound: The monomethine compound has structure of formulae (2-9).Q = same as above, preferably group having structure of formula chosen from (Cp-3), (Cp-4), (Cp-5), (Cp-7), (Cp-9), (Cp-11), (Cp-13), (Cp-17) and (Cp-18);R1 = -NR4R5 or hydroxyl;R4,R5 = hydrogen, alkyl, aryl or heterocyclic group;B1, B3 = =C(R6)- or =N-;R2,R3,R6,R7 = hydrogen or substituent;R8,R9 = same as R4;Y = oxygen atom, nitrogen atom or sulfur atom;R61 = alkyl, aryl, heterocyclic, acylamino, amino, carboxyl, alkoxyl, aryloxy, alkylthio, arylthio, ureido or alkoxy carbonyl amino;R62 = alkyl, aryl or heterocyclic group;asterisk = the position bonding with the double bond of methine group expressed with =CH-;R63, R64 = hydrogen, alkyl, alkenyl, aryl, heterocyclic, acylamino, alkyl sulfonyl amino, aryl sulfonyl amino, amino, alkoxyl, aryloxy, alkylthio, arylthio, ureido, alkoxy carbonyl amino, carbamoyl, carboxyl or alkoxy carbonyl;R65, R67 = same as R63 excluding alkenyl;R71 = hydrogen, alkyl, aryl, heterocyclic, silyl, acylamino, alkyl sulfonyl amino, aryl sulfonyl amino, amino, alkoxyl, aryloxy, alkylthio, arylthio, ureido, carboxyl or alkoxy carbonyl amino;a = 0-3;c = 0-4;R74 = carbamoyl, alkoxycarbonyl, carboxyl, cyano, sulfamoyl, acylamino, ureido, alkoxy carbonyl amino, alkyl or aryl sulfonyl amino;R75 = hydrogen, alkyl, aryl, heterocyclic, acylamino, alkyl or arylsulfonyl amino, amino, alkoxyl, alkylthio, arylthio, carboxyl, ureido, or alkoxy carbonyl amino;d = 0-4;R85,R86 = hydrogen, alkyl, aryl, heterocyclic, acylamino, alkyl sulfonyl amino, aryl sulfonyl amino, amino, alkoxyl, aryloxy, alkylthio, arylthio, ureido, alkoxy carbonyl amino, acyl, alkoxy carbonyl or carbamoyl;R87, R88 = hydrogen, alkyl, aryl, heterocyclic, aryloxy carbonyl, carboxyl, cyano, sulfamoyl, alkyl sulfonyl, aryl sulfonyl, alkoxy carbonyl, carbamoyl or nitro;R201,R22 = hydrogen, alkyl, aryl or heterocyclic group;R203, R204 = substituent;R205, R206 = hydrogen atom or substituent;P11, B12 = =C(R209)- or =N-;R212 = hydrogen, alkyl, aryl or heterocyclic group;R207-R211 = hydrogen atom or substituent, where at least one of the group of R207- R212 has at least one -COOM group via direct or connecting group, preferably R211 is -N(R301)( R302);e = 0-3;f = 0-4,; andR301, R302 = hydrogen, alkyl, aryl or heterocyclic group.R2 and R3, R3 and R4, R4 and R5, R5 and R6, and R6 and R7 are combined with each other to form a ring. R201 and R202 combines to form a cyclic structure, R202 and R205, and R202 and R206 are combined to form a cyclic structure.Preferred Property: The absorption maximum wavelength of monomethine compound (1-5) in methanol solution, is 480 nm or more. Preferred Semiconductor: The semiconductor is metal-oxide semiconductor or metal sulfide semiconductor. SPECIFIC COMPOUNDS - 260 monomethine compounds are disclosed such as compound of formula (II-1).