Organic or polymeric ferromagnet is a new kind of magnetic material．Compared with inorganic ferromagnet

the organic ferromagnet exhibits the characteristics of structural diversities

low density

and readily processing．The magnetic properties of organic magnets can be tuned by changing their molecule structure. So the synthesis of novel organic magnets is significant in the field of magnetic materials．In this article we report three poly(Schiff base)s (PBTAP

PBTMP

PBTPP) synthesized by condensation from 2

2′-diamino-4

4′-bithiazole (DABT) with 2

6-diacetypyridine(DAP)

m-phthaldialdehyde and p-phthaldialdehyde

respectively and a new series of complexes prepared from Fe2+ with the three polymers．The polymers and their Fe2+ complexes were characterized with FTIR instruments. The magnetic properties of complexes were measured by using PPMS-9 (Physical Property Measurement System)．It was found that these Fe2+ complexes were soft magnets and had relatively high saturation magnetizations．The saturation magnetization of PBTAP-Fe2+ is 6.2 emu／g

its paramagnetic Curie temperature is 88 K

and there is a magnetic hysteresis loop at 2 K．The results show that PBTAP-Fe2+ is a soft ferromagnet at low temperatures．The magnetic properties of PBTMP-Fe2+ is similar with those of PBTPP-Fe2+．The saturation magnetization of PBTMP-Fe2+ is 4.8 emu／g

and that of PBTPP-Fe2+ is 3.4 emu／g．Both of them have a negative Curie-Weiss temperature and an “S” shape magnetic hysteresis loop．These results mean that PBTPP-Fe2+ as well as PBTMP-Fe2+ exhibits ferromagnetism at low temperatures and antiferromagnetism at relatively high temperatures．