Structurally perfect spiro-bridged ladder-type poly(p-phenylene)s, which show blue fluorescence in the photoluminescence (PL) and electroluminescence (EL) emission spectra, are prepared by Suzuki-Miyaura polycondensation and Friedel-Crafts cyclization. The polymers are free of ketonic defects, exhibiting excellent thermal and color stability upon annealing in air at 110 degrees C for 24 h.