Single crystals Of L-histidine bromide monohydrate (LHB), a semiorganic nonlinear (NLO) material have been successfully grown up to a size of 22 mm x 20 mm x 9 mm. Morphology of the crystal was identified using QAD4-X-ray diffractometer. Thermal analysis of LHB crystal shows that the crystal starts its decomposition at 133.9 degrees C. The microhardness studies of the crystal confirm anisotropy in the work hardening co-efficients for different orientations. Microstructural imperfections of the LHB crystal have been studied by etching. Photoconductivity studies of LHB reveals that it exhibits positive photoconductivity. (c) 2005 Elsevier B.V. All rights reserved.