Ac omprehensive study unveiling the impacto f heterovalent doping with Bi 3 + on the structural,s emiconductive, and photoluminescent properties of as ingle crystal of lead halide perovskites (CH 3 NH 3 PbBr 3 )i sp resented.A si ndicatedb ys ingle-crystal XRD, ap erfect cubic structure in Bi 3 + -doped CH 3 NH 3 PbBr 3 crystals is maintainedina ssociation with as light lattice contraction. Time-resolved andp owerdependent photoluminescence( PL) spectroscopy illustrates ap rogressivelyq uenched PL of visible emission, alongside the appearance of an ew PL signal in the near-infrared( NIR) regime,w hich is likely to be due to energy transfer to the Bi sites. These optical characteristics indicatet he role of Bi 3 + dopants as nonradiative recombination centers, which explains the observed transition from bimolecular recombina-tion in pristine CH 3 NH 3 PbBr 3 to ad ominant trap-assisted monomolecular recombination with Bi 3 + doping. Electrically, it is found that the mobility in pristine perovskite crystals can be boosted with al ow Bi 3 + concentration,w hich may be related to atrap-filling mechanism.Aided by temperature (T)-dependentm easurements, two temperature regimes are observed in association with differenta ctivation energies (E a ) for electrical conductivity.T he reduction of E a at lower T may be ascribed to suppression of ionic conduction induced by doping. The modified electrical properties and NIR emission with the control of Bi 3 + concentration shed light on the opportunity to apply heterovalent doping of perovskite single crystals forN IR optoelectronic applications.