Single crystals of L-histidine tetrafluoroborate (L-HFB), a semiorganic nonlinear optical (NLO) material have been successfully grown by the temperature lowering and evaporation methods in our laboratory. Solubility curves of L-HFB have been determined in different solvents, such as water, ethanol and acetone. The solubility of L-HFB is very low in acetone and ethanol, therefore, it is not feasible to grow L-HFB single crystals using these solvents. Good quality single crystals of a novel nonlinear optical material L-HFB have been grown from aqueous solution. Effects of seed orientation on morphologies of L-HFB crystals were studied. The advantages and disadvantages of both the evaporation and the temperature lowering techniques are compared. The single crystals in size 20 x 20 x 10 mm(3) were grown with the deionized water as solvent in two weeks with an approximate growth rate of 1.4 mm/d. The transmission range for these crystals has been found to be from 250 to 1500 nm. (C) 1999 Elsevier Science B.V. All rights reserved.Single crystals of L-histidine tetrafluoroborate (L-HFB), a semiorganic nonlinear optical (NLO) material have been successfully grown by the temperature lowering and evaporation methods in our laboratory. Solubility curves of L-HFB have been determined in different solvents, such as water, ethanol and acetone. The solubility of L-HFB is very low in acetone and ethanol, therefore, it is not feasible to grow L-HFB single crystals using these solvents. Good quality single crystals of a novel nonlinear optical material L-HFB have been grown from aqueous solution. Effects of seed orientation on morphologies of L-HFB crystals were studied. The advantages and disadvantages of both the evaporation and the temperature lowering techniques are compared. The single crystals in size 20 x 20 x 10 mm(3) were grown with the deionized water as solvent in two weeks with an approximate growth rate of 1.4 mm/d. The transmission range for these crystals has been found to be from 250 to 1500 nm. (C) 1999 Elsevier Science B.V. All rights reserved.