Coordination between cobalt (II) ion and carbonyl group in acetone probed by using DAOSD approach

•We applied the DAOSD approach to probe weak coordination between Co2+ and acetone.•Subtle spectral variation on carbonyl band and d–d transition band are revealed.•The spectral variation suggests coordination occur between acetone and Co2+.•Coordination between acetone and Co2+ is further confirmed by EXAFS results.