In Vitro: ERCC1-XPF-IN-2 (compound 13) (0-100 µM) shows FEN-1 and DNase I activity with IC50s of >100, >100 µM, respectively. ERCC1-XPF-IN-2 slow binding kinetics with an Kd value of ~30 µM. ERCC1-XPF-IN-2 shows not toxic to Hep-G2 cells at 10 µM and relatively short mouse and human microsomal half-lives with t1/2 value of 23 min and 28 min for mouse and human, respectively.ERCC1-XPF-IN-2 (0-60 µM; 24 h) shows inhibition of nucleotide excision repair (NER) with an IC50 value of 15.6 μM in A375 cells. ERCC1-XPF-IN-2 (0-60 µM) increases the cisplatin activity with no toxicity. ERCC1-XPF-IN-2 (10 µM; 6h) causes a delay in DNA repair by a right shift towards higher numbers of γH2AX foci per cell.