A composition comprises (A) a condensation reaction catalyst, (B) a polyorganosiloxane having an average, per molecule, of at least two hydrolyzable substituents, (C) a crosslinker, and (D) a thermally conductive filler. The polyorganosiloxane may be silanol terminated, and the crosslinker may be an alkoxysilylhydrocarbylene functional polyorganosiloxane. The composition is capable of reacting via condensation reaction to form a thermally conductive product. The composition and product are useful for thermal management in (opto)electronics applications.