KTiOPO4:Ho and KTiOPO4:Er single crystals are grown by a top-seeded solution growth method from potassium phosphate and MoO3 flux. The crystalline phase, packing structure and chemical composition of the crystals are analyzed by X-ray diffraction (XRD), energy dispersive spectrum (EDS). The doping of Ho and Er induced strain in the crystal is determined from Williamson-Hall relation. The bonding between titanium and oxygen of Ho and Er doping in the KTP crystal is changing the pseudo-symmetrical deviation in the lattice. The bonding of O and Ti decreases with doping Ho and Er and Ti3+ content in the crystal. The bonding, distortion of the TiO6-TiO6 chain and change in inter-atomic distances by erbium and holmium doping are assessed by Raman spectroscopy and low temperature ESR spectroscopy which evidences the low concentration of Ti3+ presence in the crystal. The KTiOPO4:Ho and KTiOPO4:Er single crystal shows second harmonic generation properties which shows that the efficiency ratio of eta KTiOPO4:Ho/eta KTiOPO4 = 0.63 and eta KTiOPO4 :Er/eta KTiOPO4 = 0.80.