A series of new indole‐pyrazole hybrids 8a–m were synthesized through the palladium‐catalyzed ligandless Heck coupling reaction from easily accessible unsubstituted, methoxy‐ or fluoro‐substituted 4‐ethenyl‐1H‐pyrazoles and 5‐bromo‐3H‐indoles. These compounds exerted cytotoxicity to melanoma G361 cells when irradiated with blue light (414 nm) and no cytotoxicity in the dark at concentrations up to 10 µM, prompting us to explore their photodynamic effects. The photodynamic properties of the example compound 8d were further investigated in breast cancer MCF‐7 cells. Evaluation revealed comparable anticancer activities of 8d in both breast and melanoma cancer cell lines within the submicromolar range. The treatment induced a massive generation of reactive oxygen species, leading to different types of cell death depending on the compound concentration and the irradiation intensity.

Herein, we describe the synthesis of 3-(2-chloroethoxy)-1-(4-methoxyphenyl)-1H-pyrazole-4-carbaldehyde via the Vilsmeier-Haack reaction. The structure of this previously unreported compound is thoroughly elucidated through NMR, FT-IR spectroscopy and HRMS spectrometry.

The palladium-catalyzed homocoupling of 5-iodo-3,3-dimethyl-2-phenyl-3H-indole afforded 3,3,3′,3′-tetramethyl-2,2′-diphenyl-3H,3′H-5,5′-biindole in 65% yield. This previously unreported compound was fully characterized by NMR, IR and HRMS data and its optical properties were studied by UV/vis and fluorescence spectroscopy.

The ligandless palladium-catalyzed Heck reaction of 4-ethenyl-3-methoxy-1-phenyl-1H-pyrazole and 2-([1,1′-biphenyl]-4-yl)-5-bromo-3,3-dimethyl-3H-indole gave the previously unreported 2-([1,1′-biphenyl]-4-yl)-5-[(E)-2-(3-methoxy-1-phenyl-1H-pyrazol-4-yl)ethenyl]-3,3-dimethyl-3H-indole in 45% yield. The compound was characterized using NMR, FT-IR spectroscopy, and HRMS data. The optical properties of the compound were investigated in tetrahydrofuran by UV-Vis and fluorescence spectroscopy.