TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (1): 100-400 (200) mg of Ru(dcbH2)2Cl2 and 1.4-5.5 (2.73) g of TBANCS (TBA = tetrabutylammonium) are suspended in 6-24 (12) ml of a solution containing 5-20 (10) ml of dimethylformamide and 1-4 (2) ml of water. The mixture is irradiated with microwaves for 20-50 (30) minutes, at a power of 200-450 W. The solvent is evaporated and the solid dissolved twice at pH 7 in water. The solution is filtered and the Ru(dcbH2)2(NCS)2 complex is precipitated twice at pH 3 by addition of HClO4, then washed with water and dried (yield 80-85%).Preparation (2): 50-500 (250) mg of hydrated ruthenium trichloride and 70-700 (350) mg of the trpy(COOH)3 ligand are suspended in 7-70 (35) ml of dimethylformamide. The mixture is irradiated with microwaves for 5-15 (8) minutes, at a power of 250-700 (375) W. The solvent is evaporated and the solid redissolved in a small volume of methanol and reprecipitated with diethyl ether, giving 440 mg (80%) of the trichloro species.Preparation (3): 100-500 (300) mg of Ru(trpy(COOH)3)(Cl)3 and 1.5-7.9 (4.7) g of TBANCS are suspended in 15-75 (45) ml of dimethylformamide. The mixture is irradiated with microwaves for 5-20 (10) minutes, at a power of 200-450 (375) W. The solvent is evaporated and the solid dissolved at pH 9 in water by the addition of 0.1 M tetrabutylammonium hydroxide solution. The solution is filtered and the (TBA)3(Ru(trpy(COOH)(COO-)2)(NCS)3 complex precipitated in the pH range 4.8-5.0 (4.9) by addition of acid, keeping the solution in an ice bath. Yield 75-80%.Preparation (4): ((PO3H2)n(CH2)mbpy) is a bipyridine ligand which may contain one (one n = 0 and the other n = 1) or two (the two n = 1) phosphonic acid groups in 4,4' or 5,5' position, and such groups can be directly bound to the bipyridine ligand (m = 0) or attached through a methylene spacer (m = 1). The process comprises:(a) reacting a pentachlororuthenium complex or ruthenium trichloride hydrate for 3-6 (4) hours with an excess of potassium or sodium oxalate in water at 60-100 (80) deg. C;(b) adding a 1.5-2 (1.8) fold molar excess of (PO3R2)n(CH2)mbpy (R = ethyl or methyl) to obtain the complex Ru((PO3H2)n(CH2)mbpy)2(C2O4); and(c) refluxing this complex for 6-12 (8) hours in a solvent such as acetonitrile, methanol, tetrahydrofuran or acetone in the presence of a 10-40 (20) fold molar excess of acid (hydrochloric) to hydrolyze the phosphonate ester groups and at the same time to get the substitution of the oxalate ligand with two solvent molecules, to form the complex ion (Ru((PO3H2)n(CH2)mbpy)2(S)2)2+ (S represents the solvent).The solution is evaporated to dryness and the solvent complex is reacted at reflux for 2-4 (2) hours, in solvents such as methanol, ethanol or water, with an excess of monodentate ligand (X) or bidentate ligand (Y) to obtain the dye, (yield 50-80 (75-80)%).In all the preparations, the quantities can be scaled up by a factor of 10-100. EXAMPLE - None given.