Novel purine and purine isosteres containing a ferrocene motif and 4,1-disubstituted (11a−11c, 12a−12c, 13a−13c, 14a−14c, 15a−15c, 16a, 23a−23c, 24a−24c, 25a−25c) and 1,4-disubstituted (34a−34c and 35a−35c) 1,2,3-triazole rings were synthesized. The most potent cytotoxic effect on colorectal adenocarcinoma (SW620) was exerted by the 6-chloro-7-deazapurine 11c (IC₅₀ = 9.07 µM), 6-chloropurine 13a (IC₅₀ = 14.38 µM) and 15b (IC₅₀ = 15.50 µM) ferrocenylalkyl derivatives. The N-9 isomer of 6-chloropurine 13a containing ferrocenylmethylene unit showed a favourable in vitro physicochemical and ADME properties including high solubility, moderate permeability and good metabolic stability in human liver microsomes.