TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The organic compound (A) contains triazinane-containing group of formula (I, II or III), phenol group of formula (IV), or carboxylic acid group of formula (V) in one molecule. The organic compound (B) is hydrosilylation reaction product of compounds (a,b). The compound (a) is chain shape and/or cyclic polyorganosiloxane compound which have 3 or more silicon hydride groups in a molecule. The compound (b) has carbon-carbon double bond which has reactivity with silicon hydride group in a molecule. The compound (a) is of formula (VI). The compound (a) is diallyl isocyanuric acid, monoallyl isocyanuric acid, diallyl bisphenol A, diallyl bisphenol S, vinyl phenol, allyl phenol, butenonic acid, pentenoic acid, hexenoic acid, heptene acid and undecylenic acid. The organic compound (A) is of formula (VI), and has one or more epoxy groups. The organic compound (A) is triaryl isocyanurate, diallyl mono-glycidyl isocyanurate, divinylbenzene, dicyclopentadiene, trivinyl cyclohexane and vinyl norbornene. The compound (b) is cyclic polyorganosiloxane compound of formula (VII) which has silicon hydride group.R1=H or 1-50C monovalent organic group, where one or more of R1 includes carbon-carbon double bond which has reactivity with silicon hydride group;R2,R3=1-10C organic group;n=1-10;m=0-10;andm+n=3 or more. EXAMPLE - Toluene (100 g) and 1,3,5,7-tetramethyl cyclotetrasiloxane (57.49 g) were stirred at 105 degrees C. Then, xylene solution of diallyl isocyanuric acid (10 g), 1,4-dioxane (70 g), and platinum-vinyl siloxane complex (0.0186 g) with 3 weight% of platinum were dripped for 30 minutes, reaction was carried out, and reaction mixture was cooled. Unreacted 1,3,5,7-tetramethyl cyclotetrasiloxane and toluene were depressurizingly distilled, and colorless and transparent liquid was obtained. Xylene solution of diallyl mono-glycidyl isocyanurate (10.15 g), platinum-divinyl tetramethyl disiloxane complex (605 mg) with 3 weight% of platinum, and methyl boric acid (0.1 g) were stirred and defoamed to obtain mixture (i). Then, the obtained liquid (10 g), 1-ethynyl cyclohexanol (605 mg) and A-187 (RTM: ( gamma )-glycidoxy propyl trimethoxysilane) (0.5 g) were stirred to obtain mixture (ii). The obtained mixture (i) and obtained mixture (ii) were mixed to obtain curable composition. The obtained curable composition was cured to obtain cured material excellent in adhesion reliability at high temperature, optical transparency and heat resistance.