Single crystals of pure and Mg+, Ba+, Ca+ and Cu+ doped potassium pentaborate (KB5) have been grown by low temperature solution growth technique. The growth conditions and surface morphology of pure and doped single crystals of KB5 are optimized and the grown crystals are confirmed by XRD. The pure and doped crystals of KB5 are subjected to TGA and DSC studies. Using the TGA and DSC curves, the enthalpies, decomposition temperature (T-d) and weight loss are measured and the results are analysed and discussed. The influence of the presence of added dopants on the microhardness behaviour of Mg+, Ba+, Ca+ and Cu+ doped KB5 crystals are also studied and discussed. The SHG of the pure and doped samples of KB5 is confirmed by Nd:YAG pulsed laser employing the Kurtz powder technique. (C) 2002 Elsevier Science B.V. All rights reserved.