Three　metal-free　push–pull　type　organic　dyes　QX19–21　based　on　indeno[1,2-b]indole　donor　have　been　synthesized　for　dye-sensitized　solar　cells　(DSSCs).　In　order　to　obtain　good　cell　performance,　an　ethynylene　linker　was　inserted　into　the　dye　skeleton　to　extend　π-conjugated　planar　rigid　structure　and　three　hexyl　groups　were　involved　to　prevent　dye　aggregation.　The　dyes　QX19　and　QX20　employing　phenylene　and　thiophene　as　the　π-bridges　were　designed　as　a　D–π–A　structure.　As　for　the　dye　QX21,　a　benzothiadiazole　was　inserted　as　the　secondary　acceptor　to　construct　as　a　D–A–π–A　structure.　All　three　dyes　based　cells　exhibited　high　photovoltages　and　good　DSSC　performances.　A　high　PCE　of　7.99%　was　obtained　by　the　dye　QX21　under　AM　1.5G　irradiation.　Especially,　the　co-sensitization　of　QX21　with　QX20　achieved　the　further　improved　PCE　up　to　8.37%.　©　2017　Elsevier　Ltd