The surface acidic properties of a series of AlPO4-B2O3 (APB) and Al2O3-B2O3 (AIB) systems, prepared by supporting B2O3 from boric acid solutions using an incipient wetness method and containing different boria loading (5-30 wt%), have been studied by adsorption (at 573 K) of pyridine (PY) and 2,6-dimethylpyridine (DMPY) using a pulse-chromatographic method. Acidity measurements show that Lewis and Bronsted sites exist in the APE and AIB systems at all boria loadings. Moreover, the concentration of Bronsted acid sites increases with bona content. This increased surface Bronsted acidity is responsible for their improved performance in the cyclohexene skeletal isomerization (SI) reaction, to 1- and 3-methylcyclopentenes (MCPE), especially at high boria loadings. Comparison of the activity and acidity measurements points to a correlation between the activity and the number of Bronsted acid sites on the APE and AIB catalysts. Moreover,at high boron contents, AlB catalysts are more acidic and hence more active than APE catalysts. Furthermore, the more acidic catalyst (AlB, with 30 wt% boria) also showed catalytic activity for the cyclohexene hydrogen transfer (HT) reaction leading to methylcyclopentane and cyclohexane.