was then heated to reflux about 120 u00b0 c for six hours the mixture was cooled and poured into ice water and the yellow solid collected washed with water and dried at 100 u00b0 c yield was 10 7 g 98 the solid was recrystallized from n n dimethylformamide 100 ml and water 25ml using activated charcoal to give 8 6 g 79 of yellow solid m p about 390 u00b0 c anal calcd for c 36 h 26 n 4 o 2 c 79 10 h 4 79 n 10 25 found c 78 81 h 4 87 n 10 12 into a 100 ml three neck round bottom flask equipped with a mechanical stirrer thermometer nitrogen inlet moisture trap and reflux condenser was placed 1 4 bis 2 imidazolyl 4 4 hydroxyphenyl 5 phenyl benzene 2 7330 g 0 005 mol 1 3 bis 4 fluorobenzoyl benzene 1 6115 g 0 005 mol pulverized anhydrous potassium carbonate 1 6 g 0 0115 mol 15 excess dry dmac 18 ml 18 solids and toluene 25 ml the mixture was heated to about 135 u00b0 c for four hours and then heated to 155 u00b0 c overnight under nitrogen the viscous dark red solution was diluted with dmac 20 ml and precipitated into water acetic acid mixture collected washed successively in water and methanol and dried at 125 u00b0 c yield was 4 04 g 97 of yellow polymer with a glass transition temperature of 273 u00b0 c the inherent viscosity of a 0 5 solution in dmac at 25 u00b0 c was 1 38 dl g thin films cast from m cresol solution gave tensile strength tensile modulus and elongation at 25 u00b0 c of 17 600 psi 464 000 psi.