## Results  
### Spectroscopic Studies and Singlet Oxygen Generation  
The obtained Pc compounds were of intense green color and had moderate solubility in DMSO. Their absorption spectra in DMSO are shown in Figure 1 (red lines). As for phthalocyanines, two broad bands were observed--one in the UV region (Soret, B band) and the second in the red spectrum range (Q band)--which resulted from the transition of electrons from the ground state (S\({}_{0}\)) to the higher energy states (S\({}_{2}\) and S\({}_{1}\)).  
The graphite oxide flakes functionalized with Pcs were dark brown-green color. Their solubility in DMSO was very low, and most of the flakes formed suspension. To obtain samples that were stable enough to perform measurements in DMSO, ultrasonic treatment was applied. Nevertheless, partial sedimentation of the flakes occurred in time, which was registered as lower absorption intensity of GO during singlet oxygen generation measurements (Figure 2, see also Supplementary Materials and Figure S1). In the absorption spectrum of GO, characterized by lower transmission mainly in the UV-blue range, the Q band at 600-710 nm clearly appeared for both complexes (Figure 2).  
Figure 1: Absorption spectra of (**a**) bis(4-aminobutyrao)ZrPc and (**b**) bis(11-aminoundecannato)ZrPc solutions in dimethyl sulfoxide (DMSO) before and after addition of 1,3-diphenylisobenzofuran (DPBF), showing DPBF bleaching caused by singlet oxygen generation with increasing time of irradiation.  
Raman scattering spectra of both ZrPCs showed that the bands originated from macrocyclic rings and ligand chain vibrations (Figure 3a). These peaks were not recorded in the case of ZrPc/GO samples, where only D and G bands of graphite oxide were seen.  
The photoluminescence excitation spectra of bis(4-aminobutyrao)ZrPc and this complex after embedding on graphite oxide are shown in Figure 4a (monitoring emission at 700 nm). Similar spectra were recorded for the second complex and composite. The photoluminescence spectra of all investigated samples--two ZrPCs and their composites with GO--in the red-NIR range are shown in Figure 4b (excitation wavelength 620 nm), where the intensity has been normalized for better comparison.  
Figure 3: Raman spectra of investigated (a) ZrPCs and (b) ZrPc/GO samples (\(\lambda\) = 488 nm).  
Figure 2: Absorption spectra of (a) bis(4-aminobutyrao)ZrPc/GO and (b) bis(11-aminoundecannato)-ZrPc/GO suspensions in DMSO and after addition of 1,3-diphenylisobenzofuran, showing DPBF bleaching caused by singlet oxygen generation with increasing time of irradiation.  
1,3-diphenylisobenzofuran is a well-known indicator of singlet oxygen generation. The dye reacts in the presence of \({}^{1}\)O\({}_{2}\) and forms an endoperoxide, which decomposes to give 1,2-dibenzoylbenzene. This effect can be followed by measuring the decrease in absorption or fluorescence intensity of DPBF [21]. For all tested samples, the absorption band of DPBF centered at around 420 nm and gradually decreased with time of red-NIR light exposition (Figures 1 and 2). The band intensity was not changed when the samples were not irradiated, when the sole DPBF solution was irradiated, or during irradiation of GO suspension (Supplementary Materials Figure S3).