They are different socket designs and architectures. LGA 1155 being the older design. If you have an LGA 1155 i3, then one of these would be a good choice:
http://pcpartpicker.com/parts/compare/asrock-motherboard-z75pro3%2Casus-motherboard-p8b75mcsm%2Cgigabyte-motherboard-gab75md3h/
If you haven't already bought the processor, I'd seriously consider an LGA 1150 processor instead.