TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The photocatalyst comprises doped or undoped titanium dioxide. The dopant is selected from fluorine, iron, nitrogen, phosphor, and sulfur (preferably nitrogen). The dopant comprises 1:0.0001 to 1:0.5 (preferably 1:0.05 to 1: 0.25) molar ratio of titanium dioxide:dopant. The photocatalyst has a crystalline structure. The photocatalyst has a crystallite size of 5-50 (preferably 10-30) nm. The nanoporous crystalline material comprises an oxide of titanium, oxide of zirconium, oxide of zinc, oxide of tungsten, oxide of tin, barium titanate, barium strontianite, lead barium titanate, or lead zirconate (preferably titanium dioxide). The precursor is an organic precursor. The organic precursor comprises a metal organic compound containing metal alkoxide (preferably titanium alkoxide, especially titanium isopropoxide). The dopant is selected from phosphoric acid, ferric chloride, triethyl amine, trifluoroacetic acid, thiourea, silver nitrate, silver acetate, copper nitrate, copper sulfate, and/or boric acid. The power of the microwave radiation is 150-1200 (preferably 300-600) Watts. The conditions suitable to crystallize the material are non-pressurized conditions. The dopant material is present as crystallization occurs. The dopant material reduces the band gap of the crystalline material. The nanoporous crystalline material is a visible light active photocatalyst. Preferred Method: In the method, the suspension is a formed by the step of hydrolyzing the inorganic or organic precursor from its solution to precipitate an insoluble material; the suspension comprises an aqueous suspension; the nanoporous crystalline material is doped with a dopant material; and the dopant material is present in the suspension. The process further involves washing the nanoporous crystalline material to remove excess dopant material.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Preparation of nanoporous crystalline material from its inorganic or organic precursor involves preparing a suspension from the inorganic or organic precursor; and utilizing microwave irradiation, under non-pressurized conditions suitable to crystallize the material from the suspension, to crystallize the material from the suspension. EXAMPLE - Titanium (IV) isopropoxide (7.5 ml) was added to boiling water (75 ml) with constant stirring. Precipitated hydrated titanium oxide were stirred for 30 minutes, and treated with microwave radiations of power 300 W for 60 minutes. It was then filtered, dried in an oven at 80 degrees C to form catalyst powder.