Indium borate and rare earth Substituted indium borates (In(1-x)Ln(x)BO(3) (x=0.0 and 0.05; Ln=Gd. Eu, Dy and Sm)) are prepared at low temperature by metathesis reaction using InCl3, LnCl(3) and NaBO2. They are characterized by powder XRD and infrared spectroscopy. All the compositions (In(1-x)Ln(x)BO(3)) crystallize in hexagonal lattice with calcite structure. These borates gave characteristic IR vibrations of planar BO3 group. Spin-Hamiltonian parameters for Gd3+ are deduced from room temperature electron spin resonance spectrum of In0.95Gd0.05BO3. The electron spin resonance spectrum of In0.95Gd0.05BO3 gave several anisotropic lines with g > 2.0. The ESR spectrum of the sample belongs to the "intermediate" category with 1/4