Bridgman single-crystal growth of AlFe2B2 resulted in systematic Fe-Al lattice site substitution in the AlFe2B2 (Mn2AlB2-type structure, aka 1−2−2) phase along the direction of solidification. The Fe:Al ratio varied from 1.94 to 2.06. The 1−2−2 phase lattice parameters, magnetic transition temperatures (Tt) 280−315 K, magnetic entropy changes (ΔS)2.3−4.0J/kgK, heat capacity (Cp) 117−147J/molK, and thermal conductivity (κ)∼2.4−11.5W/mK all varied monotonically across the region of solubility. These findings confirm the sensitivity of the magnetic and thermal properties of the AlFe2B2 compound to antisite defects. The interplay between Al and Fe lattice site occupancy and the resultant magnetic and electronic responses facilitates tailoring the properties of the AlFe2B2 system for potential functional applications, including magnetic cooling.