NOVELTY - A chromophore, is new.    USE - The chromophore is useful in preparing a wavelength conversion luminescent medium used in a photovoltaic module and for improving the performance of a photovoltaic device of solar cell (all claimed).    ADVANTAGE - The chromophore is highly photo-stable, and can be efficiently used for wavelength conversion of visible and near IR.    DETAILED DESCRIPTION - A chromophore represented by Formula (I), is new.    Het=Formulas (1-10);    i=0 or 1-100;    D1 and D2=hydrogen, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted acyloxy, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, -aryl-NR'R'', -aryl-aryl- NR'R'', and -heteroaryl-heteroaryl-R', provided that D1 and D2 are not both hydrogen, and D1 and D2 are not optionally substituted thiophen or optionally substituted furan;    R' and R''=optionally substituted alkyl, optionally substituted alkenyl, optionally substituted aryl; and    L=optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, amino, amido, imido, optionally substituted alkoxy, acyl, carboxy, provided that L is not optionally substituted thiophene or optionally substituted furan.    X=-N(A0)-, -O-, -S-, -Se-, and -Te-;    Z=-N(Ra)-, -O-, -S-, -Se-, and -Te-;    A0=hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted acyl, optionally substituted carboxy, and optionally substituted carbonyl; and    Ra, Rb, and Rc=hydrogen, optionally substituted alkyl, optionally substituted alkoxyalkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted heteroalkenyl, optionally substituted aryl, optionally substituted arylalkyl, optionally substituted heteroaryl, optionally substituted cylcoalkyl, optionally substituted cycloalkenyl, optionally substituted cycloheteroalkyl, optionally substituted cycloheteroalkenyl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted carboxy, and optionally substituted carbonyl; or Ra and Rb, or Rb and Rc, or Ra and Rc, together form an optionally substituted ring or an optionally substituted polycyclic ring system, where each ring is independently cycloalkyl, aryl, heterocyclyl, or heteroaryl.    INDEPENDENT CLAIMS are included for:    (1) a wavelength conversion luminescent medium which comprises an optically transparent polymer matrix and at least one luminescent dye comprising the chromophore;    (2) a photovoltaic module which comprises at least one photovoltaic device or solar cell, and the wavelength conversion luminescent medium, where the wavelength conversion luminescent medium is positioned such that the incident light passes through the wavelength conversion luminescent medium prior to reaching the photovoltaic device or solar cell; and    (3) a method for improving the performance of a photovoltaic device of solar cell, which involves applying the wavelength conversion luminescent medium directly onto the light incident side of the photovoltaic device or solar cell, or encapsulate the wavelength conversion luminescent medium in the photovoltaic device or solar cell.