NOVELTY - A phosphonous acid-containing oxolane derivative (I) is new.    USE - New phosphonous acid-containing oxolane derivative is used as fluorescent and colored dyes in composition and analytical method for detecting biomolecules (all claimed) including nucleic acid, carbohydrate, amino acid, polypeptide, glycoprotein, hormone, aptamer, RNA, DNA, oligonucleotide, modified or derivatized nucleotide, enzyme, receptor, prion, receptor ligand, antibodies, antigen, toxins, bacteria, virus, blood cell and tissue cell. Can also be used for solar cell, photovoltaic device and dye laser.    ADVANTAGE - The phosphonous acid-containing oxolane derivative has excellent chemical stability, thermal stability and photochemical stability, and high fluorescent quantum yield.    DETAILED DESCRIPTION - A phosphonous acid-containing oxolane derivative of formula (I) is new.    M1,M2=moiety comprising two or more double bonds and one or more degree of conjugation, where at least one M1 is moiety comprising three or more aryl or heteroaryl;    L1,L3,L4,L6-L8=alkylene linking group or heteroalkylene linking group;    R1=H, alkyl or alkoxy;    R2=electron pair, H, alkyl, alkylether, hydroxyalkyl, aminoalkyl, hydroxyalkylether, sulfhydrylalkyl, sulfhydrylalkylether, cyanoalkyl, phospho, thiophospho, alkylphospho, alkylthiophospho, alkyletherphospho, alkyletherthiophospho, phosphoalkyl, phosphoalkylether, thiophosphoalkyl or thiophosphoalkylether, or linking group comprising covalent bond to biomolecules or microparticles;    R3=H, OH, SH, -NH2, alkyl, alkylether, hydroxyalkyl, aminoalkyl, hydroxyalkylether, sulfhydrylalkyl, sulfhydrylalkylether, cyanoalkyl, -O-aralkyl, phospho, thiophospho, alkylphospho, alkylthiophospho, -O-alkylphospho, -O-alkylthiophospho, alkyletherphospho, alkyletherthiophospho, -O-alkyletherphospho, -O-alkyletherthiophospho-phosphoalkyl, phosphoalkylether, thiophosphoalkyl, thiophosphoalkylether, -O-phosphoalkyl, -O-phosphoalkylether, -O-thiophosphoalkyl or -O-thiophosphoalkylether;    R4=O-, S-, OZ, SZ or N(R6)2;    Z=cation;    R6=H or alkyl;    R5=optionally, oxo or thioxo;    n=2-20;and    q,w=0 or 1.    INDEPENDENT CLAIMS are included for the following:    (1) staining of sample, which involves adding the phosphonous acid-containing oxolane derivative (I) to sample to produce an optical response when the sample is illuminated at specified wavelength;    (2) visual detection of biomolecules, which involves providing the phosphonous acid-containing oxolane derivative, and detecting the phosphonous acid-containing oxolane derivative by its visible properties; and    (3) composition, which comprises the phosphonous acid-containing oxolane derivative and one or more biomolecules.