This work presents the results of growth and characterization of single crystals of the antiferromagnet pure YMn2 and doped with suitably chosen chemical substitutions, using a Sn-flux technique. We particularly inspect the effects of copper (Cu) substitutions in the manganese site of YMn2, and study the dependency of the magnetic response of the material as function of the Cu-concentration. Comparing our results with the ones previously reported for polycrystals of YMn2 with regarding distinct kinds of chemical substitutions, we discuss the interplay between the new chemically induced structural, electronic and magnetic properties of this intermetallic compound.