TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The organic layer comprises a hole transport layer (103), a hole injection layer, a layer having simultaneously hole injection and hole transport functions, an electron injection layer, an electron transport layer or a layer having simultaneously electron injection and electron transport functions, where all the layers made of (I). The photoactive layer is made of an electron donor or an electron acceptor, where the electron donor is (I), and the electron acceptor is fullerene, fullerene derivatives, carbon nanotubes, carbon nanotube derivatives, basocuproin, semiconducting elements and/or semiconducting compounds. The electron donor and the electron acceptor form a bulk hetero-junction in the organic solar cell. The photoactive layer comprises thin film bilayer structure including n-type organic layer and p-type organic layer, where the p-type organic layer made of (I).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No preparation method is given. SPECIFIC COMPOUNDS - 25 Compounds (I) are specifically claimed, e.g. platinum(II) (Z)-4-oxopent-2-en-2-olate 5-(7-bromo-(1,2,5)thiadiazolo(3,4-c)pyridin-4-yl)-5'-hexyl-2,2'-bithiophen-4-ide (Ia), platinum(II) (Z)-4-oxopent-2-en-2-olate 4-(7-bromo-(1,2,5)thiadiazolo(3,4-c)pyridin-4-yl)-7-(5-hexylthiophen-2-yl)benzo(c)(1,2,5)thiadiazol-5-ide, platinum(II) (Z)-4-oxopent-2-en-2-olate 4-(7-bromo-(1,2,5)thiadiazolo(3,4-c)pyridin-4-yl)-6-fluoro-7-(5-hexylthiophen-2-yl)benzo(c)(1,2,5)thiadiazol-5-ide, platinum(II) (Z)-4-oxopent-2-en-2-olate 2-(7-bromo-(1,2,5)thiadiazolo(3,4-c)pyridin-4-yl)-5-(5-hexylthiophen-2-yl)benzen-1-ide and platinum(II) (Z)-4-oxopent-2-en-2-olate 3-(7-bromo-(1,2,5)thiadiazolo(3,4-c)pyridin-4-yl)-7-(5-hexylthiophen-2-yl)naphthalen-2-ide.    EXAMPLE - 0.5 g 7-Bromo-4-(5'-hexyl-2,2'-bithiophen-5-yl)-(1,2,5)thiadiazolo(3,4-c)pyridine was dissolved in 30 ml 2-ethoxyethanol, 10ml water and 30ml tetrahydrofuran, heated and melted to obtain mixture. Then 0.223 g potassium tetrachloroplatinate(II) was added into the mixture, refluxed for 24 hours, and dried to obtain solid. Then 0.575 g dried solid, 2.5 equivalents sodium carbonate, 2.5 equivalents 2,4-pentanedione and 50 ml 2-ethoxyethanol were mixed, reacted for 24 hours, extracted with methylene chloride, washed with water, dried over magnesium sulfate, separated and purified by silica column chromatography using hexane and methylene chloride as eluent to obtain platinum(II) (Z)-4-oxopent-2-en-2-olate 5-(7-bromo-(1,2,5)thiadiazolo(3,4-c)pyridin-4-yl)-5'-hexyl-2,2'-bithiophen-4-ide with 35% yield.