Superporous poly(vinyl imidazole) (p(VI)) cryogel was employed to prepare Co, Ni and Cu metal nanoparticles in situ. The catalytic performance of p(VI)-M cryogel composites in the degradation of methylene blue (MB) and eosin yellow (EY) and in 4-nitrophenol (4-NP) reduction in the presence of NaBH4 in aqueous media was determined as Co > Cu > Ni for MB, Co > Ni > Cu for EY and Ni approximate to Co > Cu for 4-NP. Binary and tertiary mixtures of these substrates (dyes and 4-NP) were also used to assess the best catalytic performance among the p(VI)-M composites, showing that p(VI)-Co was the best catalyst with over 95% conversion in 5 min regardless of single, binary or tertiary substrate mixtures. It was further shown that over 99% conversion for each substrate in the MB + EY + 4-NP triple mixture can be readily attained within similar to 30 min of reaction time. P(VI)-Co composite catalysts are capable of simultaneous elimination of multiple toxic organic compounds from aqueous environments, providing great opportunities in real applications.