UV absorption maxima of trimethylsilyl-, trimethylgermyl-, and trimethylstannyl-substituted pyrenes shifted to longer wavelength than that of unsubstituted pyrene. Absorption maxima of mono-, bis-, tris-, and tetrakis (trimethylsilyl) pyrenes shifted to longer wavelength consecutively at intervals of 10 nm. Fluorescence intensities and lifetimes decreased in the order of Me 3 SiAr> Me 3 GeAr> Me 3 SnAr. Fluorescence intensity of 1, 3, 6, 8-tetrakis ( ...