A curable silicone resin composition comprises (A) an uncured silicone resin having units of the formula (R*)a(R)bSiO(4−a−b)/2, where each R* is a functional group capable of reacting with Si—OH and/or Si-alkoxy groups and each R is a nonfunctional monovalent hydrocarbon group, a+b is from 1.0 to 3.0 and each molecule of uncured silicone resin contains an average of at least two groups R*, and (B) a silanol or hydrolysable compound of the formula (I) where R′ represents a hydroxyl group or a hydrolysable group; each R″ represents hydrogen, a monovalent hydrocarbon which optionally is substituted, or a group within the above definition of R′; and Ar is a substantially nonflexible linkage including at least one para-arylene moiety, so that the groups (R′)2R″Si— are spatially separated.