The compounds of 1-CCPh-2-Ph-3-(η-L)-3,1,2-RhC 2 B 9 H 9 (L=C 5 H 5 , 1, and C 5 Me 5 , 2) have been prepared. The weighted average 1 1 B-NMR chemical shift (<δ 1 1 B>) for 1 is +2.53 ppm, suggesting that the cage is distorted into a semipseudocloso structure. For 2 in CDCl 3 <δ 1 1 B> is -0.7 ppm, between that anticipated for semipseudocloso and closo forms. Compound 2 crystallises in two different forms. Orange 2a is semipseudocloso, with C(1)-C(2) 2.052(5) 9, whilst yellow 2b is essentially closo, with C(1)-C(2) 1.828(7) 9. Dissolution of both 2a and 2b in CDCl 3 affords an identical solution.