NOVELTY - An organic dye comprising substituted pyrrole group is new.    USE - As organic dye in dye-sensitized photoelectric transformation element of dye sensitized solar cell (DSSC) (claimed).    ADVANTAGE - The organic dye comprising at least one substituted pyrrole group, is capable of providing a dye sensitized solar cell (DSSC) having a good photoelectric transformation efficiency i.e. a photoelectric transformation efficiency of greater than or equal to 3.5%, and with open-circuit photovoltage (Voc), short-circuit current density (Jsc) and Fill Factor (FF) values, comparable to those of organometallic dyes of prior art. The device comprising the element having dye compound (I) has improved photoelectric transformation efficiency and reduced production costs.    DETAILED DESCRIPTION - An organic dye comprising substituted pyrrole group, of formula (I) is new.    D'=triarylamine groups of formulae (ia)-(io) or pyrrole groups of formulae (ip) to (iw);    R1-R4=hydrogen atom; or halo such as F, Cl or Br; or are selected from linear or branched 1-20C alkyl, optionally saturated, optionally containing heteroatoms, aryl optionally substituted, heteroaryl optionally substituted, cycloalkyl optionally substituted, heterocyclic groups optionally substituted, trialkyl- or triaryl-silyl, dialkyl- or diaryl-amine, dialkyl- or diaryl-phosphine, linear or branched 1-20C alkoxyl, optionally saturated, aryloxyl optionally substituted, thioalkoxyl or thioaryloxyl optionally substituted, or polyethyleneoxyl of formula R'-O-(-CH2-CH2-O)m-;or    R1 and R2 in (ip), (iii), (iil) or (iim) or R2 and R3 in (ip), (is), (iia), (iic) or (iie), or R3 and R4 in (iim), or R1 and R5 in (iu)+the other atoms to which they are bound=1-12C cycle, optionally saturated or aromatic, optionally substituted with linear or branched 1-20C alkyl, optionally saturated, optionally containing heteroatoms, aryl optionally substituted, heteroaryl optionally substituted, cycloalkyl optionally substituted, heterocyclic groups optionally substituted, trialkyl- or triaryl-silyl groups, dialkyl- or diaryl-amine, dialkyl- or diaryl-phosphine, linear or branched 1-20C alkoxyl, optionally saturated, aryloxyl optionally substituted, thioalkoxyl or thioaryloxyl optionally substituted or cyano, where the cycle optionally contains heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorus, or selenium;    R'=H, or is selected from linear or branched 1-20C alkyl;    m=1 to 20;    R5=H; or is selected from linear or branched 1-20C alkyl, optionally saturated, optionally containing heteroatoms, aryl optionally substituted, or cycloalkyl optionally substituted;    q=0 or 1;    P'=groups of formulae -(T')n-(P1)m-(P2)r-(P3)s- (Ia), -(P1)m-(T')n-(P2)r-(P3)s- (Ib), -(P1)m-(P2)r-(T')n-(P3)s- (Ic), or -(P1)m-(P2)r-(P3)s-(T')n- (Id);    T'=a triple carbon-carbon bond of formula -C?=C- (XXVII) or a double carbon-carbon bond of formula trans -C(R6)=C(R7)- (XXVIII) or cis -C(R6)=C(R7)- (XXIX), or a double nitrogen-nitrogen bond of formula trans -N=N- (XXX);    R6 and R7=H; or linear or branched 1-20C alkyl, optionally saturated, optionally containing heteroatoms, aryl optionally substituted, heteroaryl optionally substituted, or cycloalkyl optionally substituted;    n=0 to 5;    P1, P2 and P3=bivalent pyrrole groups of formulae (is), (it), (iu), (iv) or (iw) or are selected from bivalent heteroaryl or aryl of formulae (iia)-(iim);    Z=a heteroatom such as oxygen, sulfur, selenium, tellurium; or is selected from group of formula X(R8) or group of formula Y'(R9R10);    X=heteroatom such as nitrogen, phosphorus, arsenic, or boron;    Y'=carbon, silicon or germanium;    W'=heteroatom such as oxygen, sulfur, selenium, tellurium; or is selected from group of formula Y'(R9R10);    Y'=carbon, silicon or germanium atom;    R8=H; or is selected from linear or branched 1-20C alkyl, optionally saturated, optionally containing heteroatoms, aryl optionally substituted, or cycloalkyl optionally substituted;    R9 and R10=linear or branched 1-20C alkyl, optionally saturated, optionally containing heteroatoms, aryl optionally substituted, cycloalkyl optionally substituted, linear or branched 1-20C alkoxyl, optionally saturated, aryloxyl optionally substituted, thioalkoxyl or thioaryloxyl optionally substituted;    m, r and s=0 to 5;    A=COOH group; a phosphonic group of formula -PO(OH)2 or -PO(OH)(R);    R=linear or branched 1-20C alkyl; carboxycyanovinylene group of formula (iin) or (iio);    R11, R12 and R13=H; or is halo such as F, Cl or Br; or are selected from linear or branched 1-20C alkyl, optionally saturated, optionally containing heteroatoms, aryl optionally substituted, heteroaryl optionally substituted, cycloalkyl optionally substituted, cyano, or nitro;    t=1 to 6.    Provided that in compound (I), there is at least one pyrrole group of formula (ip), (iq), (ir), (is), (it), (iu), (iv), or (iw); and at least one of m, r and s is other than 0. The asterisk and dotted line indicates point of attachment. INDEPENDENT CLAIMS are included for the following:    (1) a dye-sensitized photoelectric transformation element, comprising at least one organic dye (I), where the dye-sensitized photoelectric transformation element is supported on particles of a semiconductor oxide; and    (2) a dye-sensitized solar cell (DSSC) comprising the dye-sensitized photoelectric transformation element.