Modifications in optical and electronic properties of wurtzite GaN induced by Cr doping were studied using various experimental techniques and Density Functional Theory (DFT) based calculations. Metal Oxide Chemical Vapor Deposited grown GaN/sapphire thin film samples were implanted by Cr ions at 300 keV to achieve three different doses of 5 x 10(14), 5 x 10(15) and 5 x 10(16) cm (2). X-ray diffraction, Atomic force microscopy, Spectroscopy ellipsometry, UV-vis spectrophotometery. Hall and Vibrating Sample Magnetometery measurements were carried out to study structural, optical, electrical and magnetic properties of as-grown, annealed as-grown and annealed implanted GaN samples. A dose dependent decrease in band gap of the material was observed in implanted samples. Complex refractive index, dielectric constants, energy band gap and carrier concentration based on these measurements are reported for the materials. Moreover, the results indicated substitution of Cr in host GaN lattice. Results of band structure (BS) based on DFT calculations using GGA for pure and Cr doped wurtzite GaN are also reported and discussed here. The results indicated that GaCrN is a potential material for optoelectronic and spintronics devices. (C) 2012 Elsevier B.V. All rights reserved.