Copper formate tetrahydrate [Cu(HCOO)2·4H2O], is a blue crystalline powder which is soluble in water. The formate ligand acts as organo-substitute for chlorides, sulfates, nitrates, fluorides, bromides, or nitrates. Cu(HCOO)2·4H2O has numerous uses both as a synthetic reagent in copper chemistry or as a copper source in many other applications. The Cu(HCOO)2·4H2O uses include, but are not limited to, 1. Material preservation a. preserving pulp wood and ground pulp b. mildew preventive, c. preservative for cellulose materials d. fungicidal agent, e. preserving hides in leather tanning, f. insecticidal agent g. herbicidal agent h. rot proofer for cotton fabric 2. Manufacturing a. manufacture of rayon, 3. Synthetic Chemistry & Catalysis a. catalyst for organic reactions, b. reagent for copper coordination complexes c. stabilizer for polyurethanes and nylons, High tech a. fabrication battery electrodes, b. pigment for ceramics, c. corrosion inhibitor, anticorrosion additive in lubricating oils d. cathodic material in sea water batteries, e. electroplating bath ingredient f. antifouling additive in marine paints g. textile dye ingredient in treating and staining paper h. pollution control catalyst, i. copper-containing transparent conducting ceramics precursor for solar harvesting