New experimental results on in-beam gamma spectroscopy of neutron rich boron isotopes are presented for 17B and its neutron removal fragments 14,15B, after scattering with a H2 target. A gamma transition for 17B is observed at . The fragment 15B is observed abundantly associated with a gamma transition of . This suggests for the first time a core-excited structure for 17B thereby providing a new insight into its structure. Observations for 12,14B are also presented. The data set provides a useful systematic study of first excited states of neutron rich boron isotopes showing the dramatic drop in excitation energy beyond .